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See detailAstrochemistry: The issue of molecular complexity in astrophysical environments
De Becker, Michaël ULg

in Bulletin de la Société Royale des Sciences de Liège (2013), 83

Astrochemistry aims at studying chemical processes in astronomical environments. This discipline -- located at the crossroad between astrophysics and chemistry -- is rapidly evolving and explores the ... [more ▼]

Astrochemistry aims at studying chemical processes in astronomical environments. This discipline -- located at the crossroad between astrophysics and chemistry -- is rapidly evolving and explores the issue of the formation of molecules of increasing complexity in particular physical conditions that deviate signi - cantly from those frequently encountered in chemistry laboratories. The main goal of this paper is to provide an overview of this discipline. So far, about 170 molecules have been identi ed in the interstellar medium (ISM). The presence of this molecular diversity constitutes a rm evidence that e cient formation processes are at work in the interstellar medium. This paper aims at summarizing most of present ideas that are explored by astrochemists to investigate the chemistry taking place in various astronomical environments, with emphasis on the particular conditions which are met in space (including radiation elds, cosmic-rays, low densities...). The more ambitious question of the molecular complexity is addressed following two approaches presented to be converging. The rst approach considers the growing complexity starting from the most simple chemical species in interstellar environments, and the second approach envisages successive precursors of the most complex species commonly found on Earth, and in particular in our biochemistry. The issue of molecular complexity constitutes one of the main modern scienti c questions addressed by astrochemistry, and it is used as a guideline across this paper. [less ▲]

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See detailInfluence of the water content in the synthesis of fructose laurate by immobilized lipase B of Candida antarctica (Novozym 435)
Olive, Gilles ULg; Pompeu Torezan, Gabriela A.; Blecker, Christophe ULg

in Bulletin de la Société Royale des Sciences de Liège (2012), 81(2012), 82-89

New synthesis conditions for a direct esterification of fructose by lauric acid with Novozym 435 as a catalyst are reported in this paper. With these new conditions, a conversion rate of 72% was achieved ... [more ▼]

New synthesis conditions for a direct esterification of fructose by lauric acid with Novozym 435 as a catalyst are reported in this paper. With these new conditions, a conversion rate of 72% was achieved, which is almost the same value as in the case of transesterification where no water as by-product is produced (74.6 %). The conversion rate of these reactions can be modeled as a function of the initial water content by a three-parameter power law for the esterification and by an exponential law for the transesterification. The influence of the water content on the mono over di-ester ratio will also be discussed to a lesser extent. [less ▲]

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See detailUne brève histoire des centres réactionnels de la photosynthèse
Franck, Fabrice ULg

in Bulletin de la Société Royale des Sciences de Liège (2012), 81

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See detailLes énergies marines
Beckers, Jean-Marie ULg

in Bulletin de la Société Royale des Sciences de Liège (2012), 81

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See detailA first orbital solution for the non-thermal radio emitter Cyg OB2 #9
Nazé, Yaël ULg; Damerdji, Yassine ULg; Rauw, Grégor ULg et al

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

We reported in 2008 the first detection of the binary nature of Cyg OB2 #9. Since then, we have continued our spectroscopic monitoring of this object, doubling the number of available spectra of the star ... [more ▼]

We reported in 2008 the first detection of the binary nature of Cyg OB2 #9. Since then, we have continued our spectroscopic monitoring of this object, doubling the number of available spectra of the star while covering a second periastron passage. Using a variety of techniques, the radial velocities were estimated and a first, preliminary orbital solution was derived (P=2.4 yrs). The mass ratio appears close to unity and the eccentricity is large, 0.7-0.75. [less ▲]

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See detailStudy of a possible X-ray sensor based on the Plasmon Surface Resonance for the next generation of instruments
Hervé, Anthony ULg; Hastanin, Juriy ULg; Habraken, Serge ULg et al

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

With the new generation of X-ray space observatories, such as IXO in preparation, we explore a new technology in order to improve the spectral resolution and the sensitivity of future instruments. We have ... [more ▼]

With the new generation of X-ray space observatories, such as IXO in preparation, we explore a new technology in order to improve the spectral resolution and the sensitivity of future instruments. We have studied the possibility to create a sensor based on the Surface Plasmon Resonance (SPR), already used in chemistry and biomedical applications, and have determined the preliminary constraints on its size, energy resolution and working temperature. [less ▲]

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See detailHerschel-PACS observations of Nebulae Ejected by Massive Stars
Vamvatira Nakou, Chloi ULg; Royer, Pierre; Hutsemekers, Damien ULg et al

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

The study of the nebulae ejected from Luminous Blue Variables and the circumstellar bubbles around Wolf-Rayet stars, which radiate strongly in the infrared due to the heating of dust, is crucial for the ... [more ▼]

The study of the nebulae ejected from Luminous Blue Variables and the circumstellar bubbles around Wolf-Rayet stars, which radiate strongly in the infrared due to the heating of dust, is crucial for the understanding of the massive stars evolution. With Herschel we are able to observe these objects in the far-infrared region. In the context of the Mass-loss from Evolved StarS guaranteed time key program, we obtained imaging and spectroscopic observations of nebulae associated with Luminous Blue Variable and Wolf-Rayet stars using PACS, one of the three instruments on-board Herschel. A description of these observations, data analysis and preliminary results are presented. [less ▲]

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See detailThe multiwavelength view of hot, massive stars
Rauw, Grégor ULg; De Becker, Michaël ULg; Nazé, Yaël ULg et al

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

Massive stars are certainly among the most fascinating objects of stellar populations. They trigger many astrophysical processes from star formation to the chemical enrichment of the interstellar medium ... [more ▼]

Massive stars are certainly among the most fascinating objects of stellar populations. They trigger many astrophysical processes from star formation to the chemical enrichment of the interstellar medium. Yet, their properties are still not fully understood and these objects are therefore at the core of many ongoing research activities. With the advent of new, high-performance, ground-based and space-borne facilities, the multi-wavelength investigation of hot, massive stars has definitely been boosted over the last decade. It is indeed nowadays possible to study these objects over a wide part of the electromagnetic spectrum, all the way from radio waves to gamma-rays. Motivated by this fact, we decided to organize a conference devoted to this topic in the framework of the well-established series of Liege International Astrophysical Colloquia (LIAC). The resonance in the community was extremely positive, with many proposals for high-quality contributions. During the week of 12 - 16 July 2010, 138 astrophysicists, from institutes in 21 countries all over the world, gathered in Liege to discuss how the multi-wavelength approach has revolutionized their research on massive stars. The colloquium was organized into five thematic sessions, and the present proceedings are organized along the same chapters: (1) stellar winds, diagnostics across the electromagnetic spectrum; (2) massive star formation, confronting theory and observation; (3) evolution and interaction of massive stars with their environment; (4) future instrumentation and its application to massive star research; (5) massive binaries: interaction and evolution. [less ▲]

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See detailMixing in magnetic OB stars
Morel, Thierry ULg

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

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See detailThe Mons campaign on OB stars
Morel, Thierry ULg; Rauw, Grégor ULg; Eversberg, T. et al

in Bulletin de la Société Royale des Sciences de Liège (2011), 80

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See detailModélisation intégrée du cycle de l'eau : méthodologie et perspectives
Deliège, Jean-François ULg

in Bulletin de la Société Royale des Sciences de Liège (2010), 79

Au delà du rappel contextuel (cycle de l’Eau, Modélisation et Modélisation Intégrée), l'objectif vise à présenter des Modèles Descriptifs et Physiquement Basés existant et à investiguer la similitude des ... [more ▼]

Au delà du rappel contextuel (cycle de l’Eau, Modélisation et Modélisation Intégrée), l'objectif vise à présenter des Modèles Descriptifs et Physiquement Basés existant et à investiguer la similitude des besoins de connaissance de la qualité de l'eau relativement aux problématiques (i) accident (impact court terme, impact long terme), (ii) changement Climatique (impact long terme). Il est également proposé un modèle conceptuel opérationnel orienté quantité puis qualité de l'eau et capable de simuler par exemple les effets de la gestion anthropique, tant à court qu'à long terme (Changement climatique). [less ▲]

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See detailStudying bright, massive stars in the era of large telescopes I. General context
Rauw, Grégor ULg

in Bulletin de la Société Royale des Sciences de Liège (2010), 79

Stars of spectral type O play a key role in many processes in our Galaxy and beyond. However, there are still a number of open issues about these massive and luminous objects that need to be ad-dressed ... [more ▼]

Stars of spectral type O play a key role in many processes in our Galaxy and beyond. However, there are still a number of open issues about these massive and luminous objects that need to be ad-dressed. Several of these questions require (long-term) spectroscopic monitoring that is difficult to achieve with the highly-demanded equipment on most modern professional instruments. However, these kinds of studies offer an opportunity for collaborations between amateur spectroscopists and professional astrophysicists. [less ▲]

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See detailStudying bright, massive stars in the era of large telescopes II : Wind structures
Morel, Thierry ULg

in Bulletin de la Société Royale des Sciences de Liège (2010), 79

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See detailEvolution de la vie pendant les quatre premiers milliards d’années
Javaux, Emmanuelle ULg

in Bulletin de la Société Royale des Sciences de Liège (2009), 79

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See detailDarwin en Antarctique: diversité et phylogénie
Wilmotte, Annick ULg

in Bulletin de la Société Royale des Sciences de Liège (2009), 78

In the first part, I imagine that Charles Darwin has visited Livingston Island in the Antarctic Peninsula. In the first part, our research on the cyanobacterial diversity in the region of the Belgian ... [more ▼]

In the first part, I imagine that Charles Darwin has visited Livingston Island in the Antarctic Peninsula. In the first part, our research on the cyanobacterial diversity in the region of the Belgian research station Princess Elisabeth is presented. [less ▲]

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See detailStratégies comportementales de reproduction chez les animaux
Denoël, Mathieu ULg

in Bulletin de la Société Royale des Sciences de Liège (2007), 76

Biological diversity often refers to species counts but it also encompasses the amazing displayed reproductive strategies. Males and females exhibit adaptations which are not necessarily associated with ... [more ▼]

Biological diversity often refers to species counts but it also encompasses the amazing displayed reproductive strategies. Males and females exhibit adaptations which are not necessarily associated with the production of gametes. This sexual dimorphism is in part due to sexual selection, i.e. mate choice and competition within the sexes. The use of sometimes complex models allows to highlight the adaptive signification of strategies and then to explain their exhibition in varied situations. Each species is characterised by the existence of specific traits, but within each species, males and females are not constrained to exhibit a stereotyped strategy. In function of their phenotypic peculiarities and the surrounding environment, both sexes can opt for behavioural alternatives that optimize their reproductive success. This plasticity can lead to the exhibition of particular displays but also to the formation of monogamous or polygamous breeding systems. Selection does not stop at the reproductive act as varied strategies can favour a sexual partner over another one in a sexual conflict which can be pronounced, but which can also have bilateral advantages. Such a sperm competition – as acting at the gamete level – can result in sperm male precedence by the exhibition of guarding behaviour, physical or chemical manipulations and also by cryptic sperm choice. [less ▲]

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See detailLa titanite de Bertrix et les minéraux associés.
Rondeux, Mélanie ULg; Hatert, Frédéric ULg

in Bulletin de la Société Royale des Sciences de Liège (2007), 76

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See detailLe monde souterrain : la genèse des cavernes
Ek, Camille ULg

in Bulletin de la Société Royale des Sciences de Liège (2006), 75

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See detailSpectroscopy of Massive Stars
Nazé, Yaël ULg

in Bulletin de la Société Royale des Sciences de Liège (2006), 75

Although rare, massive stars, being the main sources of ionizing radiation, chemical enrichment and mechanical energy in the Galaxy, are the most important objects of the stellar population. This review ... [more ▼]

Although rare, massive stars, being the main sources of ionizing radiation, chemical enrichment and mechanical energy in the Galaxy, are the most important objects of the stellar population. This review presents the many different aspects of the main tool used to study these stars, i.e. spectroscopy. The first part consists in an introduction on these objects and their physical properties (mass, wind, evolution, relation with their environment). Next, the spectral behaviour of single massive stars is investigated, in the visible as well as in the X-ray domain. Finally, the last part of this paper deals with massive binaries, especially those exhibiting a colliding wind phenomenon. [less ▲]

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See detailTemps physique et temps culturels : le cas de l’Égypte ancienne
Winand, Jean ULg

in Bulletin de la Société Royale des Sciences de Liège (2005), 74(4), 311-325

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