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
See detailLong baseline interferometry applied to the study of colliding-wind massive binaries: current status and prospects for the near future
De Becker, Michaël ULg

Conference (2011, April 04)

Massive binaries are important laboratories to investigate science topics related to stellar astrophysics. In particular, colliding winds in some massive binaries are known to produce strong X-ray ... [more ▼]

Massive binaries are important laboratories to investigate science topics related to stellar astrophysics. In particular, colliding winds in some massive binaries are known to produce strong X-ray emission, to accelerate particles, and to act as nucleation site for dust particles. Recent advances in the development of interferometric instruments coupled to long baseline facilities such as the VLTI allow us to observe astronomical targets at the milli-arcsecond scale. In the context of the study of colliding-wind binaries, this tool is likely to provide crucial information. I will briefly discuss ongoing observation campaigns aiming at using such interferometric facilities in the purpose to study the physics of colliding-wind binaries. [less ▲]

Detailed reference viewed: 10 (0 ULg)
See detailLong baseline interferometry applied to the study of massive stars: current observations and prospects for VSI
De Becker, Michaël ULg

Conference (2009, February 19)

Recent advances in the development of interferometric instruments coupled to long baseline facilities such as the VLTI allow us to observe astronomical targets at the milli-arcsecond scale. In the context ... [more ▼]

Recent advances in the development of interferometric instruments coupled to long baseline facilities such as the VLTI allow us to observe astronomical targets at the milli-arcsecond scale. In the context of the study of massive stars, this new tool is likely to provide crucial information on the multiplicity of massive stars, and on interactions in colliding-wind binaries. In this context, our group is leading observation campaigns with the VLTI aiming at investigating massive multiple systems. I will briefly present these campaigns and discuss prospects for observations with next generation instruments such as the VLTI-Spectro-Imager (VSI). [less ▲]

Detailed reference viewed: 11 (0 ULg)
See detailLong baseline interferometry as a tool to investigate colliding-wind massive binaries
De Becker, Michaël ULg

Conference (2009, March 20)

Massive stars present the interesting property to generate strong stellar winds. In the particular case of binary systems made of two massive stars, the two stellar winds are likely to collide. In ... [more ▼]

Massive stars present the interesting property to generate strong stellar winds. In the particular case of binary systems made of two massive stars, the two stellar winds are likely to collide. In addition, in this scenario, interesting physics is occurring, such as strong high-energy emission, dust production or even particle acceleration. However, our capability to understand these "higher-level" processes relies intimately on our knowledge of stellar and orbital parameters of these binaries, and on our vision of the hydrodynamics that is taking place in these objects. In this context, the purpose of this presentation is to discuss the expected contribution of long baseline interferometry. [less ▲]

Detailed reference viewed: 10 (1 ULg)
Full Text
See detailLong baseline interferometry: a promising tool for multiplicity investigations of massive stars
De Becker, Michaël ULg

in Revista Mexicana de Astronomía y Astrofísica (2010, February), 38

Massive binaries are crucial laboratories that allow us to investigate processes occurring in quite extreme conditions, such as particle acceleration, high-energy emission, or even dust formation. All ... [more ▼]

Massive binaries are crucial laboratories that allow us to investigate processes occurring in quite extreme conditions, such as particle acceleration, high-energy emission, or even dust formation. All these processes are intimately dependent on binarity. Our understanding of the underlying physics strongly requires preliminary multiplicity studies likely to uncover still undetected binaries, and determine their orbital parameters. However, classical spectroscopic approaches sometimes fail to provide a solution to this issue. Long baseline interferometry turns out to be a promising complementary technique to address the question of the multiplicity of massive stars. A campaign has been initiated with the VLTI to take benefit of this technique. [less ▲]

Detailed reference viewed: 18 (6 ULg)
Full Text
See detailLong E-mails and Internet Connections
Merciadri, Luca ULg

E-print/Working paper (2009)

Fetching e-mails is a daily task. However, when an e-mail size overcomes a given threshold, e-mail communication becomes more difficult, because slow. This is principally due to the outgoing speed of ... [more ▼]

Fetching e-mails is a daily task. However, when an e-mail size overcomes a given threshold, e-mail communication becomes more difficult, because slow. This is principally due to the outgoing speed of cheap Internet connections. We propose here a mechanism which limits this problem. [less ▲]

Detailed reference viewed: 99 (23 ULg)
See detailLong fibrosis
Clercx, Cécile ULg

in proceedings 35 Internationaler Fortbildungskurs Kleintierkrankheiten (2014, February)

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailLong lasting instabilities in granular mixtures
Caps, Hervé ULg; Michel, Renaud; Lecocq, N. et al

in Physica A: Statistical Mechanics and its Applications (2003), 326(3-4), 313-321

We have performed experiments of axial segregation in the Oyama's drum. We have tested binary granular mixtures during very long times. The segregation patterns have been captured by a CCD camera and ... [more ▼]

We have performed experiments of axial segregation in the Oyama's drum. We have tested binary granular mixtures during very long times. The segregation patterns have been captured by a CCD camera and spatio-temporal graphs are created. We report the occurrence of instabilities which can last several hours! We stress that those instabilities originate from the competition between axial and radial segregations. We put into evidence the occurrence of giant fluctuations in the fraction of grain species along the surface during the unstable periods. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 8 (4 ULg)
Full Text
See detailLong Neogene kinematic history and late Quaternary order-of-magnitude acceleration of the south Tianshan foldbelt, Kuqa basin, China
Suppe, J; Wang, X; Hubert, Aurelia ULg

in Geophysical Research Abstracts (2009, April), 11

Detailed reference viewed: 5 (2 ULg)
Full Text
Peer Reviewed
See detailThe long period eccentric orbit of the particle accelerator HD 167971 revealed by long baseline interferometry
De Becker, Michaël ULg; Sana, H; Absil, Olivier ULg et al

in Monthly Notices of the Royal Astronomical Society (2012), 423

Using optical long baseline interferometry, we resolved for the first time the two wide components of HD167971, a candidate hierarchical triple system known to efficiently accelerate particles. Our multi ... [more ▼]

Using optical long baseline interferometry, we resolved for the first time the two wide components of HD167971, a candidate hierarchical triple system known to efficiently accelerate particles. Our multi-epoch VLTI observations provide direct evidence for a gravitational link between the O8 supergiant and the close eclipsing O + O binary. The separation varies from 8 to 15 mas over the three-year baseline of our observations, suggesting that the components evolve on a wide and very eccentric orbit (most probably e>0.5). These results provide evidence that the wide orbit revealed by our study is not coplanar with the orbit of the inner eclipsing binary. From our measurements of the near-infrared luminosity ratio, we constrain the spectral classification of the components in the close binary to be O6-O7, and confirm that these stars are likely main-sequence objects. Our results are discussed in the context of the bright non-thermal radio emission already reported for this system, and we provide arguments in favour of a maximum radio emission coincident with periastron passage. HD167971 turns out to be an efficient O-type particle accelerator that constitutes a valuable target for future high angular resolution radio imaging using VLBI facilities. [less ▲]

Detailed reference viewed: 26 (7 ULg)
See detailThe long period eccentric orbit of the particle accelerator HD167971 revealed by long baseline interferometry
De Becker, Michaël ULg

Conference (2012, March 12)

Particle acceleration and non-thermal emission processes in colliding-wind massive binaries constitute key issues in massive stars physics. The investigation of such processes requires a good knowledge of ... [more ▼]

Particle acceleration and non-thermal emission processes in colliding-wind massive binaries constitute key issues in massive stars physics. The investigation of such processes requires a good knowledge of their stellar, stellar wind and orbital parameters. In this short contribution, I will present the latest results related to the case of HD167971, a system recently resolved by the VLTI. The information on the separation and on the luminosity ratio derived from these observations will also be discussed in the context of the so-called 'standard scenario' for particle acceleration and non-thermal processes in massive stars. [less ▲]

Detailed reference viewed: 14 (1 ULg)
Peer Reviewed
See detailLong protocols to Rorschach Comprehensive System and a posteriori reduction of number of responses: What is the impact on the clinical interpretation ?
Dufour, Cristelle; Englebert, Jérôme ULg; Blavier, Adelaïde ULg

Poster (2014, May 27)

Our study was interested in the exceptionally long protocols, superior to 55 answers, supplied by five subjects in the test of Rorschach according to the method of the Comprehensive System. In order to ... [more ▼]

Our study was interested in the exceptionally long protocols, superior to 55 answers, supplied by five subjects in the test of Rorschach according to the method of the Comprehensive System. In order to gain understanding of which attitude to adopt in front of this kind of protocol, we made a a posteriori reduction of the number of answers by basing us on the recommendations of Exner (Exner, on 2001), then a comparative study between the clinical interpretation realized with all of the answers and with only the first five answers by board. We also replicate this methodology of a posteriori decrease of the number of answers with four answers by board according to the new recommendations of the system R-PAS of Meyer and al. (Meyer and al, on 2009). The sample consists of three raw coal subjects and two psychiatric subjects. Our analysis highlighted a stability of certain variables (EB, Lambda, EA for example) but a difference in the psychological profile of the subjects after reduction. We observed a clarification of the fundamental difficulties to the psychiatric subjects and rather a neutralization of these difficulties for the raw coal subjects, with particularly defence mechanisms which seem more adapted. In our sample, the consideration of all of the answers or only of the partial protocol thus brings a difference in the clinical interpretation ; as a consequence any reduction should be made with big caution. Our study allows to discuss current practices of the test of Rorschach, by looking for a compromise between the inherent constraints to the validity of the test and the questions of the clinical complexity decrease appropriate to any initiative of standardization. [less ▲]

Detailed reference viewed: 24 (2 ULg)
Full Text
Peer Reviewed
See detailLong range seasonal movements of northern pike (Esox lucius L.) in the barbel zone of the River Ourthe (River Meuse basin, Belgium).
Ovidio, Michaël ULg

in Aquatic telemetry: advances and applications (2005)

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were ... [more ▼]

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were captured by electric fishing in November 2000 and January 2001. They were surgically implanted with a radio-transmitter and tracked for 149 to 349 days in a 30-km river stretch. During the pre-spawning period in winter, most movements were between distinct holding areas spaced from 40 to 550 m. All the pike began the upstream spawning migration between 8 February and 30 March 2001, when the mean water temperature varied from 6.7°C to 8.7 °C and the water flow from 52 to 199 m3s-1. The six pike travelled upstream, over distances ranging from 0.75 km to 15.7 km to reach their potential spawning sites. Pike arrived on their potential spawning sites between the 13 February and the 02 April 2001 and remained there from 5 to 25 days when the daily mean water temperature ranged from 2.9 to 10.0 °C. The six pike moved downstream after spawning and showed similar behaviour to those observed prior to spawning, but the distances between holding areas were more extended than during the winter pre-spawning period. When considering the entire tracking period, the longitudinal extension of the activity domains ranged 1 421 to 24 798 m (mean 12,050 m). This exploratory study provided original observations on northern pike movements in a barbel zone of the River Meuse basin. Results contrasted with the widely established view of pike being a sedentary predator and provides data on its behaviour throughout the annual cycle. [less ▲]

Detailed reference viewed: 160 (11 ULg)
Peer Reviewed
See detailLong range seasonal movements of northern pike (Esox lucius L.) in the barbel zone of the River Ourthe (River Meuse basin, Belgium).
Ovidio, Michaël ULg; Philippart, Jean-Claude ULg

Conference (2003, June)

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were ... [more ▼]

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were captured by electric fishing in November 2000 and January 2001. They were surgically implanted with a radio-transmitter and tracked for 149 to 349 days in a 30-km river stretch. During the pre-spawning period in winter, most movements were between distinct holding areas spaced from 40 to 550 m. All the pike began the upstream spawning migration between 8 February and 30 March 2001, when the mean water temperature varied from 6.7°C to 8.7 °C and the water flow from 52 to 199 m3s-1. The six pike travelled upstream, over distances ranging from 0.75 km to 15.7 km to reach their potential spawning sites. Pike arrived on their potential spawning sites between the 13 February and the 02 April 2001 and remained there from 5 to 25 days when the daily mean water temperature ranged from 2.9 to 10.0 °C. The six pike moved downstream after spawning and showed similar behaviour to those observed prior to spawning, but the distances between holding areas were more extended than during the winter pre-spawning period. When considering the entire tracking period, the longitudinal extension of the activity domains ranged 1 421 to 24 798 m (mean 12,050 m). This exploratory study provided original observations on northern pike movements in a barbel zone of the River Meuse basin. Results contrasted with the widely established view of pike being a sedentary predator and provides data on its behaviour throughout the annual cycle. [less ▲]

Detailed reference viewed: 75 (3 ULg)
Full Text
Peer Reviewed
See detailLong run behaviour of Pacific-Basin stock prices
Corhay, Albert ULg; Tourani-Rad, Alireza; Urbain, Jean-Pierre ULg

in Applied Financial Economics (1995), 5(1), 11-18

In this paper, we investigate the long run relationship among five major Pacific-Basin stock markets. We focus on the common long run behaviour of their stock price indices over a sample period of 20 ... [more ▼]

In this paper, we investigate the long run relationship among five major Pacific-Basin stock markets. We focus on the common long run behaviour of their stock price indices over a sample period of 20 years. Using cointegration theory, we find that while there exists a rather integrated Pacific Basin financial area, the regional aspects (Asian versus Pacific) play important roles. [less ▲]

Detailed reference viewed: 29 (6 ULg)
Full Text
Peer Reviewed
See detailThe Long Run Performance of Malaysian Initial Public Offerings (IPOs): Value and Growth Effects
Corhay, Albert ULg; Teo, Stanley; Tourani Rad, Alireza

in Managerial Finance (2002), 28(2), 52-64

Detailed reference viewed: 32 (2 ULg)
Peer Reviewed
See detailLong term (3 years) prevention of trabecular postmenopausal bone loss with low dose intermittent nasal salmon calcitonin
Reginster, Jean-Yves ULg; DEROISY, Rita ULg; Albert, Adelin ULg et al

in Revue du Rhumatisme et des Maladies Osteo-Articulaires (1992), 59

Detailed reference viewed: 6 (2 ULg)
Full Text
Peer Reviewed
See detailLong term agreement between two different centres regarding joint space narrowing measurement in knee osteoarthritis
Deroisy, Rita ULg; Roux, J. P.; Bruyère, Olivier ULg et al

in Osteoporosis International (2010, May), 21(Suppl.1), 233-234

Detailed reference viewed: 21 (4 ULg)
Full Text
Peer Reviewed
See detailLong term behaviour of the Boom Clay: influence of viscosity on the pore pressure distribution
Coll, Cécile; Charlier, Robert ULg; Li, Xiang Ling et al

Conference (2007)

Detailed reference viewed: 40 (6 ULg)
Full Text
Peer Reviewed
See detailLong Term Carbon Dioxide Exchange Above A Mixed Forest In The Belgian Ardennes
Aubinet, Marc ULg; Chermanne, B.; Vandenhaute, M. et al

in Agricultural and Forest Meteorology (2001), 108(4),

Detailed reference viewed: 26 (5 ULg)
Full Text
See detailLong term carbon dioxide exchange above a mixed forest in the Belgian Ardennes: evaluation of different approaches to deduce total ecosystem respiration from Eddy covariance measurements
Jerome, Elisabeth ULg; Heinesch, Bernard ULg; Aubinet, Marc ULg

Poster (2010, May 05)

The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 ... [more ▼]

The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 flux measurements started in 1996 and are still going on. Thirteen complete years of measurements are thus available. Net Ecosystem Exchange (NEE) inter annual variability may be driven by gross primary productivity (GPP) or Total Ecosystem Respiration (TER), which should thus be both quantified. Using flux partitioning methods, TER is deduced from NEE measurements. GPP is then obtained by subtracting TER from NEE. Initially, a robust estimation of TER is required. This work seeks to compare two independent approaches to assess TER in order to quantify the implications on inter-annual variability. The comparison was performed on twelve complete years. TER estimates can be deduced by extrapolating to the whole day NEE measurements taken during selected night or day periods. In both case, the extrapolation is performed by using a respiration response to temperature. The first approach, referred as the night-time approach, consisted in calculating TER using a temperature response function derived from night-time data sets (Reichstein et al., 2005). The second approach, referred as the daytime approach, consisted in assessing TER from the intercept of the NEE/Photosynthetically Photon Flux Density (PPFD) response (Wohlfahrt et al., 2005). For each approach, different modalities were compared: the use of long term (annual) or short term (15 days) data sets for the night-time approach and the use of different types of regression for the daytime approach. In addition, the impact of the temperature choice was studied for each of the approaches. For the night-time approach, main results showed that air temperature sensitivity of ecosystem respiration derived from annual data did not reflect the short-term air temperature sensitivity. Vielsalm is a summer active ecosystem (annual temperature sensitivity larger than short-term temperature sensitivity). Results suggested also that, for both approaches, regressions based on soil temperature gave more robust results than those based on air temperature. Furthermore, the comparison showed that the night-time and the daytime approaches give disagreeing pictures of TER inter annual variability which suggested that the choice of the approach is critical in order to correctly depict TER inter annual variability. Finally, at this stage, TER inter annual variability cannot be explained by variability of climatic conditions. [less ▲]

Detailed reference viewed: 64 (8 ULg)