Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailObservations and asteroseismological analysis of the rapid subdwarf B pulsator EC 09582-1137
Randall, Suzanna K.; Van Grootel, Valérie ULg; Fontaine, Gilles et al

in Astronomy and Astrophysics (2009), 507

We made photometric and spectroscopic observations of the rapidly pulsating subdwarf B star EC 09582-1137 with the aim of determining the target's fundamental structural parameters from asteroseismology ... [more ▼]

We made photometric and spectroscopic observations of the rapidly pulsating subdwarf B star EC 09582-1137 with the aim of determining the target's fundamental structural parameters from asteroseismology. This analysis forms part of a long-term programme geared towards distinguishing between different proposed formation scenarios for hot B subdwarfs on the basis of their internal characteristics. So far, secure asteroseismic solutions have been computed for 9 of these pulsators, and first comparisons with results from evolutionary calculations look promising. The new data comprise 30 h of fast time-series photometry obtained with SUSI2 at the NTT on La Silla, Chile, as well as 1 h of low-resolution spectroscopy gathered with EMMI, also mounted on the NTT. From the photometry we detected 5 independent harmonic oscillations in the 135-170 s period range with amplitudes up to 0.5% of the mean brightness of the star. In addition, we extracted two periodicities interpreted as components of a rotationally split multiplet that indicate a rotation period of the order of 2-5 days. We also recovered the first harmonic of the dominant pulsation, albeit at an amplitude below the imposed 4σ detection threshold. The spectroscopic observations led to the following estimates of the atmospheric parameters of EC 09582-1137: T_eff = 34 806±233 K, log{g} = 5.80±0.04, and log N(He)/N(H) = -1.68±0.06. Using the observed oscillations as input, we searched in model parameter space for unique solutions that present a good fit to the data. Under the assumption that the two dominant observed periodicities correspond to radial or dipole modes, we were able to isolate a well-constrained optimal model that agrees with the atmospheric parameters derived from spectroscopy. The observed oscillations are identified with low-order acoustic modes with degree indices ℓ = 0, 1, 2, and 4 and match the computed periods with a dispersion of 0.57%. Non-adiabatic calculations reveal all theoretical modes in the observed period range to be unstable, an important a posteriori consistency check for the validity of the optimal model. The inferred structural parameters of EC 09582-1137 are T_eff = 34 806 K (from spectroscopy), log{g} = 5.788±0.004, Mast = 0.485±0.011 Msun, log{(M_env/Mast)} = -4.39±0.10, R = 0.147±0.002 Rsun, and L = 28.6±1.7 Lsun. We additionally derive the absolute magnitude MV = 4.44±0.05 and the distance d = 1460±66 pc. [less ▲]

Detailed reference viewed: 9 (1 ULg)
Peer Reviewed
See detailObservations and comments on the Walloon Competitive Clusters
Antoine, Mélanie ULg

Conference (2008, January)

In recent years, the promotion of R&D partnerships between universities, research labs and companies has become a key feature of innovation and development public policies. However, these collaborations ... [more ▼]

In recent years, the promotion of R&D partnerships between universities, research labs and companies has become a key feature of innovation and development public policies. However, these collaborations turn out to be fragile and their management very complex. In our literature review, the congruence between the nature of innovations (i.e. their radicalness) and the cooperation practices appears as a potentially powerful explanatory factor of interfirm innovation project’s outcome. Following this hypothesis, we explore, on two case studies of projects subsidized by the Walloon Competitive Clusters program, the way actors innovate and organize their actions. Though they face similar constraints, these projects illustrate diverse configurations, not only as to the nature of innovations but also as to cooperation practices. Besides, the analysis reveals that the criteria used to characterize the nature of innovations do not necessarily form a homogeneous set of factors. Considering these observations, we try to identify the main challenges faced by both projects’ partners. [less ▲]

Detailed reference viewed: 38 (5 ULg)
See detailObservations and physical properties of small solar system bodies
Gérard, Jean-Claude ULg; Brahic, André; Surdej, Jean ULg

Book published by Université de Liège (1992)

Detailed reference viewed: 26 (9 ULg)
See detailLes observations astronomiques au dehors de l’atmosphère terrestre
Swings, Polydore ULg

Book published by Centre National de Recherches de l’Espace. (1960)

Detailed reference viewed: 9 (2 ULg)
Full Text
See detailObservations astronomiques et magnétiques exécutées sur le territoire de l'Etat Indépendant du Congo par A. Delporte et L. Gillis: rapport de F. Folie
Folie, François ULg

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1893), 3e série, t. 25(6), 661-665

The author establishes a report on A. Delporte and L. Gillis’ work on the astronomical and magnetic observations executed on the Congo Free State territory.

Detailed reference viewed: 3 (0 ULg)
Peer Reviewed
See detailObservations au large de Calvi en régime d'été
Djenidi, Salim ULg

in Bulletin de la Société Royale des Sciences de Liège (1985), 54(6), 287-300

Detailed reference viewed: 5 (3 ULg)
Peer Reviewed
See detailObservations au microscope electronique a balayage de cellules nerveuses de moelle spinale d'embryons de poulet cultivees in vitro sur de la polylysine-L.
Noel-Courtey, B.; Heinen, Ernst ULg

in Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences. Série D, Sciences Naturelles (1977), 285(4), 385-7

Chick embryo nerve cells from the lumbo-sacral spinal cord have been isolated by trypsinisation and cultivated in Rose chambers on polylysine-L as a substrate. The cells are analysed by scanning electron ... [more ▼]

Chick embryo nerve cells from the lumbo-sacral spinal cord have been isolated by trypsinisation and cultivated in Rose chambers on polylysine-L as a substrate. The cells are analysed by scanning electron microscopy. The mode of adherence of these cells to the substrate and the modifications of the surface of the neuroblasts during their transformation into neurocytes are studied. [less ▲]

Detailed reference viewed: 81 (7 ULg)
Full Text
See detailObservations coupled to the overpasses of the polar vortex over mid-latitude Europe in winter 1995-1996
Hennen, Olivier; De Mazière, Martine; Van Roozendael, Michel et al

in Harris, N. R. P.; Kilbane-Dawe, I.; Amanatidis, G.T. (Eds.) Polar stratospheric ozone 1997 (1998)

The spring 1996 polar vortex was very deep and cold, with temperatures down to the ice formation threshold, and persisted until March. The northern hemisphere ozone decrease in winter 1995-1996 was larger ... [more ▼]

The spring 1996 polar vortex was very deep and cold, with temperatures down to the ice formation threshold, and persisted until March. The northern hemisphere ozone decrease in winter 1995-1996 was larger than ever before in the nineties. Particularly at the European mid-latitudes, transport of air masses from the polar vortex towards mid-latitudes had a noticeable impact on the stratospheric temperatures and composition. Such was not observed that clearly in the latest winter 1996-1997. In this work, signatures of polar vortex overpasses in spring 1996 at several European mid-latitude stations are indicated. Most significant events have been observed at these stations with a delay of one to four days, on the following days: 18-22/1, 14-20/2, 1-6/3, 29/3, 15-17/4. The focus here will be on the two events in March. [less ▲]

Detailed reference viewed: 22 (1 ULg)
Full Text
See detailObservations d'occultation d'étoiles par la Lune et d'éclipses des satellites de Jupiter
Folie, François ULg

in Astronomische Nachrichten (1886), 115(2754), 299-300

Table resuming a series of observations of stars occultation made by the Moon and Jupiter moon eclipses produced by E. Stuyvaert at the Brussels Royal Observatory in 1885 and 1886 and communicated by ... [more ▼]

Table resuming a series of observations of stars occultation made by the Moon and Jupiter moon eclipses produced by E. Stuyvaert at the Brussels Royal Observatory in 1885 and 1886 and communicated by François Folie. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
See detailObservations de comètes et d'occultations d'étoiles par la lune
Folie, François ULg

in Astronomische Nachrichten (1886), 114(2718), 91-94

Table resuming a series of observations of comets and stars occultation made by the Moon produced by E. Stuyvaert at the Brussels Royal Observatory in 1885 and 1886 and communicated by François Folie.

Detailed reference viewed: 3 (0 ULg)
Full Text
See detailObservations de comètes et de planètes
Folie, François ULg

in Astronomische Nachrichten (1887), 117(2793), 145-147

Table resuming a series comets and planets observations produced by E. Stuyvaert at the Brussels Royal Observatory in 1885 and 1886 and communicated by François Folie.

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
See detailObservations de coupes dans la terrasse T3 dans la vallée du Niger en aval de Niamey
Willems, Luc ULg; Bergoing, Jean-Pierre

in Revue de Géographie Alpine (1994), 5

Dans la région de Niamey, l'étendue et le nombre d'affleurements du complexe T3, appelé aussi terrasse moyenne, permettent de dresser une chronologie relative des événements climatiques survenus dans la ... [more ▼]

Dans la région de Niamey, l'étendue et le nombre d'affleurements du complexe T3, appelé aussi terrasse moyenne, permettent de dresser une chronologie relative des événements climatiques survenus dans la région durant son édification. Une étude systématique révèle une grande diversité dans les dépôts souvent assimilable aux variations locales de sédimentation. Cependant, cinq épisodes majeurs dans l'édification du complexe peuvent être dégagés et correspondent à autant de fluctuations climatiques durant une période qui s'étendrait de 20 000 à 12 000 BP. La découverte et l'observation de diaclases ainsi que des phénomènes de soutirage dans les dépôts pléistocènes montrent le rôle important qu'a pu jouer la fracturation du socle birrimien sur l'ensemble de la morphologie actuelle de la région de Niamey, en particulier sur le réseau hydrographique. [less ▲]

Detailed reference viewed: 16 (0 ULg)
Full Text
See detailObservations de deux polarissimes à Uccle
Folie, François ULg

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1894), 3e série, t. 27(4), 482-491

During observations, the author notices the existence of two variable stars and records it in his notes.

Detailed reference viewed: 3 (0 ULg)
Full Text
See detailObservations de l'étoile de Gore près de χ1 Orionis
Folie, François ULg

in Astronomische Nachrichten (1887), 116(2769), 137-140

Observations of the Gore’s stars near χ1 Orionis made by the author in 1885 and 1886.

Detailed reference viewed: 5 (0 ULg)
Full Text
See detailObservations de l’Univers lointain avec le Télescope Spatial Hubble
Surdej, Jean ULg

in Nouvelles de la Science et des Technologies (1990), 8(Nø3-4), 87-92

Detailed reference viewed: 11 (2 ULg)
Full Text
See detailObservations de la Comète 1887 IV, d'occultations d'étoiles par la Lune et d'éclipses des Satellites de Jupiter
Folie, François ULg

in Astronomische Nachrichten (1888), 119(2837), 75-78

Table resuming a series of Comet 1887 IV observations, of stars occultation by the Moon and Jupiter moons eclipses produced by E. Stuyvaert at the Brussels Royal Observatory in 1887 and communicated by ... [more ▼]

Table resuming a series of Comet 1887 IV observations, of stars occultation by the Moon and Jupiter moons eclipses produced by E. Stuyvaert at the Brussels Royal Observatory in 1887 and communicated by François Folie. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
See detailObservations de la Comète 1888 III (Brooks Août 7)
Folie, François ULg

in Astronomische Nachrichten (1888), 120(2872), 253-254

Table resuming a series of Comet 1888 III observations produced by E. Stuyvaert at the Brussels Royal Observatory and communicated by François Folie.

Detailed reference viewed: 4 (0 ULg)
Full Text
See detailObservations des phénomènes naturels en avril 1896
Folie, François ULg

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1896), 3e série, t. 31

The author resumes various observations of natural phenomena which occurred in April 1896.

Detailed reference viewed: 3 (0 ULg)
Full Text
See detailObservations des phénomènes naturels en mars 1896
Folie, François ULg

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1896), 3e série, t. 31

The author resumes various observations of natural phenomena which occurred in March 1896

Detailed reference viewed: 6 (0 ULg)