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See detailMassive non-thermal radio emitters: new data and their modelling
Volpi, D.; Blomme, R.; De Becker, Michaël ULg et al

Poster (2011)

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See detailA massive parsec-scale dust ring nebula around the yellow hypergiant Hen 3-1379
Hutsemekers, Damien ULg; Cox, N. L. J.; Vamvatira-Nakou, Chloi ULg

in Astronomy and Astrophysics (2013), 552

On the basis of far-infrared images obtained by the Herschel Space Observatory, we report the discovery of a large and massive dust shell around the yellow hypergiant Hen 3-1379. The nebula appears as a ... [more ▼]

On the basis of far-infrared images obtained by the Herschel Space Observatory, we report the discovery of a large and massive dust shell around the yellow hypergiant Hen 3-1379. The nebula appears as a detached ring of 1 pc diameter which contains 0.17 M[SUB]&sun;[/SUB] of dust. We estimate the total gas mass to be 7 M[SUB]&sun;[/SUB], ejected some 1.6 × 10[SUP]4[/SUP] years ago. The ring nebula is very similar to nebulae found around luminous blue variables (LBVs) except it is not photoionized. We argued that Hen 3-1379 is in a pre-LBV stage, providing direct evidence that massive LBV ring nebulae can be ejected during the red supergiant phase. [less ▲]

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See detailMassive renal and adrenal calcifications in a young dialysis patient with familial Mediterranean fever
Delanaye, Pierre ULg; Krzesinski, Jean-Marie ULg

in Nephrology Dialysis Transplantation (2005), 20(1), 238-238

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See detailThe massive runaway stars HD 14633 and HD 15137
Boyajian, T. S.; Beaulieu, T. D.; Gies, D. R. et al

in Astrophysical Journal (2005), 621(2, Part 1), 978-984

We present results from a radial velocity study of two runaway O-type stars, HD14633 (ON8.5V) and HD 15137 [O9.5 III(n)]. We find that HD 14633 is a single-lined spectroscopic binary with an orbital ... [more ▼]

We present results from a radial velocity study of two runaway O-type stars, HD14633 (ON8.5V) and HD 15137 [O9.5 III(n)]. We find that HD 14633 is a single-lined spectroscopic binary with an orbital period of 15.4083 days. The second target, HD 15137, is a radial velocity variable and a possible single-lined spectroscopic binary with a period close to 1 month. Both binaries have large eccentricity, small semiamplitude, and a small mass function. We show the trajectories of the stars in the sky based on an integration of motion in the Galactic potential, and we suggest that both stars were ejected from the vicinity of the open cluster NGC 654 in the Perseus spiral arm. The binary orbital parameters and runaway velocities are consistent with the idea that both these stars were ejected by supernova explosions in binaries and that they host neutron star companions. We find that the time of flight since ejection is longer than the predicted evolutionary timescales for the stars. This discrepancy may indicate that the stars have a lower mass than normally associated with their spectral classifications, that they were rejuvenated by mass transfer prior to the supernova, or that their lives have been extended through rapid rotation. [less ▲]

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See detailThe massive star binary fraction in young open clusters - I. NGC 6231 revisited
Sana, H.; Gosset, Eric ULg; Nazé, Yaël ULg et al

in Monthly Notices of the Royal Astronomical Society (2008), 386(1), 447-460

We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain the ... [more ▼]

We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain the fundamental properties of the O-star population. Almost three quarters of the O-type stars in the cluster are members of a binary system. The minimum binary fraction is 0.63, with half the O-type binaries having an orbital period of the order of a few days. The eccentricities of all the short-period binaries are revised downward, and henceforth match a normal period-eccentricity distribution. The mass ratio distribution shows a large preference for O + OB binaries, ruling out the possibility that, in NGC 6231, the companion of an O-type star is randomly drawn from a standard initial mass function. Obtained from a complete and homogeneous population of O-type stars, our conclusions provide interesting observational constraints to be confronted with the formation and early evolution theories of O-stars. [less ▲]

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See detailThe massive star binary fraction in young open clusters - II. NGC6611 (Eagle Nebula)
Sana, H.; Gosset, Eric ULg; Evans, C. J.

in Monthly Notices of the Royal Astronomical Society (2009), 400

Based on a set of over 100 medium- to high-resolution optical spectra collected from 2003 to 2009, we investigate the properties of the O-type star population in NGC6611 in the core of the Eagle Nebula ... [more ▼]

Based on a set of over 100 medium- to high-resolution optical spectra collected from 2003 to 2009, we investigate the properties of the O-type star population in NGC6611 in the core of the Eagle Nebula (M16). Using a much more extended data set than previously available, we revise the spectral classification and multiplicity status of the nine O-type stars in our sample. We confirm two suspected binaries and derive the first SB2 orbital solutions for two systems. We further report that two other objects are displaying a composite spectrum, suggesting possible long-period binaries. Our analysis is supported by a set of Monte Carlo simulations, allowing us to estimate the detection biases of our campaign and showing that the latter do not affect our conclusions. The absolute minimal binary fraction in our sample is f[SUB]min[/SUB] = 0.44 but could be as high as 0.67 if all the binary candidates are confirmed. As in NGC6231 (see Paper I), up to 75 per cent of the O star population in NGC6611 are found in an O+OB system, thus implicitly excluding random pairing from a classical IMF as a process to describe the companion association in massive binaries. No statistical difference could be further identified in the binary fraction, mass-ratio and period distributions between NGC6231 and NGC 6611, despite the difference in age and environment of the two clusters. [less ▲]

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See detailThe massive star binary fraction in young open clusters - III. IC 2944 and the Cen OB2 association
Sana, H.; James, G.; Gosset, Eric ULg

in Monthly Notices of the Royal Astronomical Society (2011), 416

Using an extended set of multi-epoch high-resolution high signal-to-noise ratio optical spectra, we readdress the multiplicity properties of the O-type stars in IC 2944 and in the Cen OB2 association. We ... [more ▼]

Using an extended set of multi-epoch high-resolution high signal-to-noise ratio optical spectra, we readdress the multiplicity properties of the O-type stars in IC 2944 and in the Cen OB2 association. We present new evidence of binarity for five objects and we confirm the multiple nature of another two. We derive the first orbital solutions for HD 100099, HD 101436 and HD 101190 and we provide additional support for HD 101205 being a quadruple system. The minimal spectroscopic binary fraction in our sample is f[SUB]min[/SUB]= 0.57. Using numerical simulations, we show that the detection rate of our observational campaign is close to 90 per cent, leaving thus little room for undetected spectroscopic binary systems. The statistical properties of the O-star population in IC 2944 are similar, within the uncertainties, to the results obtained in the earlier papers in this series despite the fact that sample size effects limit the significance of the comparison. Using newly derived spectroscopic parallaxes, we reassess the distance to IC 2944 and obtained 2.3 ± 0.3 kpc, in agreement with previous studies. We also confirm that, as far as the O stars are concerned, the IC 2944 cluster is most likely a single entity. [less ▲]

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See detailMassive stars and emission-line stars with GAIA
Blomme, Ronny; Frémat, Y.; Lobel, Alex et al

Poster (2009)

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See detailMassive Stars and High-Energy Emission in OB Associations
Rauw, Grégor ULg; Nazé, Yaël ULg; Blomme, Ronny et al

Book (2005)

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See detailMassive Stars in the Gaia-ESO Survey
Blomme, Ronny; Fremat, Yves; Lobel, Alex et al

in Massive Stars: From alpha to Omega (2013, June 01)

The Gaia-ESO Survey (GES) is an ambitious project to study the formation and evolution of the Milky Way and its stellar populations. It is led by Gerry Gilmore and Sofia Randich and includes about 350 Co ... [more ▼]

The Gaia-ESO Survey (GES) is an ambitious project to study the formation and evolution of the Milky Way and its stellar populations. It is led by Gerry Gilmore and Sofia Randich and includes about 350 Co-Investigators. During 300 nights (spread over 5 years) of order 10^5 Giraffe spectra and 10^4 UVES spectra will be taken. As part of the survey, about 13 clusters will be observed that were chosen specifically for their massive-star content. We report on the preliminary analysis of GES data from two such clusters: NGC 3293 and NGC 6705. We determine stellar parameters for the B-type stars in NGC 3293 and compare the A-type stars population between the two clusters. We also use a repeat observation to study binarity and use the radial velocity information to study cluster membership in NGC 3293. We also list our plans for future observations, which include the Carina nebula region. [less ▲]

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See detailMassive stars, a lifetime of influence
Nazé, Yaël ULg

Poster (2010)

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See detailMassive stars: privileged sources of cosmic-rays for interstellar astrochemistry
De Becker, Michaël ULg

in Bulletin de la Société Royale des Sciences de Liège (2015, January), 84

Massive stars can be considered as crucial engines for interstellar physics. They are indeed the main providers of UV radiation field, and constitute a substantial source of chemical enrichment. On their ... [more ▼]

Massive stars can be considered as crucial engines for interstellar physics. They are indeed the main providers of UV radiation field, and constitute a substantial source of chemical enrichment. On their evolution time-scale (at most about 10 Myr), they typically stay close to their formation site, i.e. close to molecular clouds very rich in interstellar molecules. These stellar objects have also the property to be involved in particle acceleration processes leading to the production of high energy charged particles (cosmic-rays). After rejection in the interstellar medium, these particles will play a substantial role in processes such as those simulated in various facilities dedicated to experimental astrochemistry. This short contribution intends to put these particles, crucial for astrochemistry, in their adequate astrophysical context. [less ▲]

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See detailMast cells and IgE in defense against venoms: Possible "good side" of allergy?
Galli, Stephen J.; Starkl, Philipp; Marichal, Thomas ULg et al

in Allergology international : official journal of the Japanese Society of Allergology (2015)

Physicians think of mast cells and IgE primarily in the context of allergic disorders, including fatal anaphylaxis. This 'bad side' of mast cells and IgE is so well accepted that it can be difficult to ... [more ▼]

Physicians think of mast cells and IgE primarily in the context of allergic disorders, including fatal anaphylaxis. This 'bad side' of mast cells and IgE is so well accepted that it can be difficult to think of them in other contexts, particularly those in which they may have beneficial functions. However, there is evidence that mast cells and IgE, as well as basophils (circulating granulocytes whose functions partially overlap with those of mast cells), can contribute to host defense as components of adaptive type 2 immune responses to helminths, ticks and certain other parasites. Accordingly, allergies often are conceptualized as "misdirected" type 2 immune responses, in which IgE antibodies are produced against any of a diverse group of apparently harmless antigens, as well as against components of animal venoms. Indeed, certain unfortunate patients who have become sensitized to venoms develop severe IgE-associated allergic reactions, including fatal anaphylaxis, upon subsequent venom exposure. In this review, we will describe evidence that mast cells can enhance innate resistance to reptile or arthropod venoms during a first exposure to such venoms. We also will discuss findings indicating that, in mice which survive an initial encounter with venom, acquired type 2 immune responses, IgE antibodies, the high affinity IgE receptor (FcvarepsilonRI), and mast cells can contribute to acquired resistance to the lethal effects of both honeybee venom and Russell's viper venom. These findings support the hypothesis that mast cells and IgE can help protect the host against venoms and perhaps other noxious substances. [less ▲]

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See detailMast cells: potential positive and negative roles in tumor biology.
Marichal, Thomas ULg; Tsai, Mindy; Galli, Stephen J.

in Cancer Immunology Research (2013), 1

Mast cells are immune cells that reside in virtually all vascularized tissues. Upon activation by diverse mechanisms, mast cells can secrete a broad array of biologically active products that either are ... [more ▼]

Mast cells are immune cells that reside in virtually all vascularized tissues. Upon activation by diverse mechanisms, mast cells can secrete a broad array of biologically active products that either are stored in the cytoplasmic granules of the cells (e.g., histamine, heparin, various proteases) or are produced de novo upon cell stimulation (e.g., prostaglandins, leukotrienes, cytokines, chemokines, and growth factors). Mast cells are best known for their effector functions during anaphylaxis and acute IgE-associated allergic reactions, but they also have been implicated in a wide variety of processes that maintain health or contribute to disease. There has been particular interest in the possible roles of mast cells in tumor biology. In vitro studies have shown that mast cells have the potential to influence many aspects of tumor biology, including tumor development, tumor-induced angiogenesis, and tissue remodeling, and the shaping of adaptive immune responses to tumors. Yet, the actual contributions of mast cells to tumor biology in vivo remain controversial. Here, we review some basic features of mast cell biology with a special emphasis on those relevant to their potential roles in tumors. We discuss how using in vivo tumor models in combination with models in which mast cell function can be modulated has implicated mast cells in the regulation of host responses to tumors. Finally, we summarize data from studies of human tumors that suggest either beneficial or detrimental roles for mast cells in tumors. [less ▲]

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See detailMastectomie bilaterale prophylactique chez les patientes a tres haut risque de cancer mammaire: au-dela de la technique...
BLERET, Valerie ULg; Cusumano, P.; DEZFOULIAN, Bahram ULg et al

in Revue Médicale de Liège (2011), 66(5-6), 250-3

Bilateral prophylactic mastectomy is the most efficient risk management strategy for women at very high risk for breast cancer. Different methods can be used. The implementation of such a strategy must ... [more ▼]

Bilateral prophylactic mastectomy is the most efficient risk management strategy for women at very high risk for breast cancer. Different methods can be used. The implementation of such a strategy must respond to the request of a well informed patient. [less ▲]

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See detailMaster Class on Migration and Integration
Martiniello, Marco ULg

Scientific conference (2010, January 28)

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See detailUn master en ligne sous la loupe
Poumay, Marianne ULg

in Distances et Savoirs (2006), 4(1),

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See detailMaster equation for collective spontaneous emission with quantized atomic motion
Damanet, François ULg; Braun, Daniel; Martin, John ULg

Scientific conference (2016, March 02)

We derive a markovian master equation for the internal dynamics of an ensemble of two-level atoms including the quantization of their motion. Our equation provides a unifying picture of the effects of ... [more ▼]

We derive a markovian master equation for the internal dynamics of an ensemble of two-level atoms including the quantization of their motion. Our equation provides a unifying picture of the effects of recoil and indistinguishability of atoms beyond the Lamb-Dicke regime on both their dissipative and conservative dynamics. We give general expressions for the decay rates and the dipole-dipole shifts for any motional states, generalizing those in Ref. [1]. We find closed-form formulas for a number of relevant states (gaussian states, Fock states and thermal states). In particular, we show that dipole-dipole interactions and cooperative photon emission [2] can be modulated through the external state of motion. As an application of our general formalism, we study the spatial Pauli blocking of two fermionic atoms beyond the Lamb-Dicke regime [3]. [1] G. S. Agarwal, Springer Tracts In Modern Physics 70, 1 (1974). [2] R. H. Dicke, Phys. Rev. 93, 99 (1954). [3] R. M. Sandner, M. Müller, A. J. Daley & P. Zoller, Phys. Rev. A 84, 043825 (2011). [less ▲]

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See detailMaster equation for collective spontaneous emission with quantized atomic motion
Damanet, François ULg; Braun, Daniel; Martin, John ULg

in Physical Review A (2016), 93

We derive a Markovian master equation for the internal dynamics of an ensemble of two-level atoms including all effects related to the quantization of their motion. Our equation provides a unifying ... [more ▼]

We derive a Markovian master equation for the internal dynamics of an ensemble of two-level atoms including all effects related to the quantization of their motion. Our equation provides a unifying picture of the consequences of recoil and indistinguishability of atoms beyond the Lamb-Dicke regime on both their dissipative and conservative dynamics, and applies equally well to distinguishable and indistinguishable atoms. We give general expressions for the decay rates and the dipole-dipole shifts for any motional states, and we find closed-form formulas for a number of relevant states (Gaussian states, Fock states, and thermal states). In particular, we show that dipole-dipole interactions and cooperative photon emission can be modulated through the external state of motion. [less ▲]

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