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See detailDark Atoms and Dark Radiation
Khlopov, Maxim; Belotsky, Konstantin; Cudell, Jean-René ULg et al

Book published by Hindawi Publishing Corporation (2014)

We have invited investigators to contribute original research and review articles that seek to define the possible physical nature of composite dark matter and its constituents, to stimulate the ... [more ▼]

We have invited investigators to contribute original research and review articles that seek to define the possible physical nature of composite dark matter and its constituents, to stimulate the experimental searches and to suggest astrophysical tests for their effects. The collected papers in this special issue represent only a first small step in the approach to the thorough investigation of the topic of dark atoms and dark radiation, demonstrating the wide but far from complete variety of possible aspects of this problem. [less ▲]

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See detailDark atoms and the positron-annihilation-line excess in the galactic bulge
Cudell, Jean-René ULg; Khlopov, Maxim; Wallemacq, Quentin ULg

in Advances in High Energy Physics (2014), 2014

It was recently proposed that stable particles of charge -2, O^{--}, can exist and constitute dark matter after they bind with primordial helium in O-helium (OHe) atoms. We study here in details the ... [more ▼]

It was recently proposed that stable particles of charge -2, O^{--}, can exist and constitute dark matter after they bind with primordial helium in O-helium (OHe) atoms. We study here in details the possibility that this model provides an explanation for the excess of gamma radiation in the positron-annihilation line from the galactic bulge observed by INTEGRAL. This explanation assumes that OHe, excited to a 2s state through collisions in the central part of the Galaxy, de-excites to its ground state via an E0 transition, emitting an electron-positron pair. The cross section for OHe collisions with excitation to 2s level is calculated and it is shown that the rate of such excitations in the galactic bulge strongly depends not only on the mass of O-helium, which is determined by the mass of O^{--}, but also on the density and velocity distribution of dark matter. Given the astrophysical uncertainties on these distributions, this mechanism constrains the O^{--} mass to lie in two possible regions. One of these is reachable in the experimental searches for stable multicharged particles at the LHC. [less ▲]

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See detailDark matter and LHC phenomenology in a left-right supersymmetric model
Esteves, J. N.; Romao, J. C.; M., Hirsch et al

in Journal of High Energy Physics [=JHEP] (2012), 1201

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See detailDark Matter in a SUSY Left-Right Model
Vicente, Avelino ULg

in Journal of Physics: Conference Series (2012), 375

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See detailDark matter in a SUSY left-right theory
Vicente, Avelino ULg

Poster (2011)

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See detailDark matter, édité -- J. Audouze et J. Tran Thanh Van
Manfroid, Jean ULg

in Ciel et Terre (1989), 105

Not Available

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See detailDarkness promotes flowering in the absolute long-day requiring plant, Lolium temulentum L. Ceres
Périlleux, Claire ULg; Bernier, Georges ULg; Kinet, Jean-Marie

in Journal of Experimental Botany (1997), 48(307), 349--351

Vegetative plants of the long-day grass Lolium temulentum L. Ceres were exposed to threshold long days or light breaks. Protracted darkness given just afterwards clearly promoted flowering and was weakly ... [more ▼]

Vegetative plants of the long-day grass Lolium temulentum L. Ceres were exposed to threshold long days or light breaks. Protracted darkness given just afterwards clearly promoted flowering and was weakly inductive on its own. The promotive effect of darkness was restricted to floral induction since further apical development was weak. [less ▲]

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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 detailDarwin ground-based European nulling interferometer experiment (GENIE)
Gondoin, Philippe; Absil, Olivier ULg; Fridlund, C V Malcolm et al

in Traub, Wesley (Ed.) Interferometry for Optical Astronomy II (2003, February 01)

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterize ... [more ▼]

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterize their atmospheres. Darwin is conceived as a space "nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The present paper will describe the objectives and the status of the project. [less ▲]

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See detailThe Darwin Ground-based European Nulling Interferometry Experiment
Gondoin, P.; Absil, Olivier ULg; Fridlund, M. et al

in Lacoste, H. (Ed.) GENIE - DARWIN Workshop - Hunting for Planets (2003, March 01)

Darwin is one of the most challenging space pro jects ever considered by the European Space Agency (ESA). Its principal ob jectives are to detect Earth-like planets around nearby stars and to characterise ... [more ▼]

Darwin is one of the most challenging space pro jects ever considered by the European Space Agency (ESA). Its principal ob jectives are to detect Earth-like planets around nearby stars and to characterise their atmospheres. Darwin is conceived as a space nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the o -axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The present paper will describe the ob jectives and the status of the project. [less ▲]

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See detailThe Darwin mission within ESA’s Cosmic Vision
Absil, Olivier ULg

Scientific conference (2007, July 03)

Durant cet exposé, je présenterai la mission Darwin telle que proposée à l'ESA par un groupe de scientifiques européens et internationaux. Darwin s'inscrit parfaitement dans le Thème 1 du programme Cosmic ... [more ▼]

Durant cet exposé, je présenterai la mission Darwin telle que proposée à l'ESA par un groupe de scientifiques européens et internationaux. Darwin s'inscrit parfaitement dans le Thème 1 du programme Cosmic Vision: "What are the Conditions for Planet Formation and the Emergence of Life?". Je présenterai le cas scientifique de Darwin, qui a pour but principal de détecter et caractériser des planètes habitables semblables à la Terre autour d'étoiles du voisinage solaire. En complément à ce volet axé sur la planétologie comparée et l'astrobiologie, le cas scientifique de Darwin comprend aussi un volet consacré à l'imagerie à haute résolution angulaire d'objets astrophysiques et extragalactiques de types variés. Je m'attarderai finalement sur les avancées obtenues récemment tant sur le design de la mission que sur les technologies associées, qui devraient permettre d'atteindre ces objectifs dans le cadre de la première mission "Large" du programme Cosmic Vision et dans une enveloppe budgétaire raisonnable. [less ▲]

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See detailDarwin---an experimental astronomy mission to search for extrasolar planets
Cockell, Charles S; Herbst, Tom; Léger, Alain et al

in Experimental Astronomy (2009), 23

As a response to ESA call for mission concepts for its Cosmic Vision 2015--2025 plan, we propose a mission called Darwin. Its primary goal is the study of terrestrial extrasolar planets and the search for ... [more ▼]

As a response to ESA call for mission concepts for its Cosmic Vision 2015--2025 plan, we propose a mission called Darwin. Its primary goal is the study of terrestrial extrasolar planets and the search for life on them. In this paper, we describe different characteristics of the instrument. [less ▲]

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See detailDarwin-A Mission to Detect and Search for Life on Extrasolar Planets
Cockell, C. S.; Léger, A.; Fridlund, M. et al

in Astrobiology (2009), 9(1)

The discovery of extrasolar planets is one of the greatest achievements of modern astronomy. The detection of planets that vary widely in mass demonstrates that extrasolar planets of low mass exist. In ... [more ▼]

The discovery of extrasolar planets is one of the greatest achievements of modern astronomy. The detection of planets that vary widely in mass demonstrates that extrasolar planets of low mass exist. In this paper, we describe a mission, called Darwin, whose primary goal is the search for, and characterization of, terrestrial extrasolar planets and the search for life. Accomplishing the mission objectives will require collaborative science across disciplines, including astrophysics, planetary sciences, chemistry, and microbiology. Darwin is designed to detect rocky planets similar to Earth and perform spectroscopic analysis at mid-infrared wavelengths (6-20 mum), where an advantageous contrast ratio between star and planet occurs. The baseline mission is projected to last 5 years and consists of approximately 200 individual target stars. Among these, 25-50 planetary systems can be studied spectroscopically, which will include the search for gases such as CO[SUB]2[/SUB], H[SUB]2[/SUB]O, CH[SUB]4[/SUB], and O[SUB]3[/SUB]. Many of the key technologies required for the construction of Darwin have already been demonstrated, and the remainder are estimated to be mature in the near future. Darwin is a mission that will ignite intense interest in both the research community and the wider public. [less ▲]

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See detailThe Darwin-GENIE Experiment: An ESA-ESO Partnership
Gondoin, Ph; Absil, Olivier ULg; Erd, C. et al

in Sembach, K. R.; Blades, J. C.; Illingworth, G. D. (Eds.) et al Hubble's Science Legacy: Future Optical/Ultraviolet Astronomy from Space (2003)

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See detailDarwin-GENIE: a nulling instrument at the VLTI
Gondoin, Philippe A; Absil, Olivier ULg; den Hartog, Roland H et al

in Traub, Wesley (Ed.) New Frontiers in Stellar Interferometry (2004, October 01)

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise ... [more ▼]

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise their atmospheres. Darwin is conceived as a space "nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The instrument will operate in the L' band around 3.8 mum, where the thermal emission from the telescopes and the atmosphere is reduced. GENIE will be able to operate in two different configurations, i.e. either as a single Bracewell nulling interferometer or as a double-Bracewell nulling interferometer with an internal modulation scheme. [less ▲]

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See detailDarwin: required performance (invited)
Absil, Olivier ULg

Scientific conference (2007, December 06)

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See detailLe darwinisme peut-il tout expliquer ?
Baurain, Denis ULg

Conference given outside the academic context (2005)

Vus d'Europe, les procès opposant les farouches défenseurs du darwinisme à leurs pugnaces détracteurs ont de quoi faire sourire. Certes, il n'y a pas qu'aux Etats-Unis que l'on puisse encore trouver des ... [more ▼]

Vus d'Europe, les procès opposant les farouches défenseurs du darwinisme à leurs pugnaces détracteurs ont de quoi faire sourire. Certes, il n'y a pas qu'aux Etats-Unis que l'on puisse encore trouver des Chrétiens fondamentalistes persuadés que Dieu a créé la Terre en six jours. En revanche, aucun gouvernement de nos contrées n'aurait l'idée saugrenue de faire interdire l'enseignement de la théorie de l'évolution dans nos écoles, ni même de l'autoriser à la condition expresse de la traiter sur le même pied que le créationnisme inspiré d'une lecture littérale de la Genèse. Cela dit, croire que le refus de l'évolution par "sélection naturelle des mutations favorables" se limite aux couches populaires de l'Amérique conservatrice serait inexact. En réalité, les plus acharnés des tenants du créationnisme pur et dur -- ou de son avatar à peine plus subtil, l'Intelligent Design -- sont généralement des intellectuels, voire dans certains cas des biologistes qui ont renoncé à toute carrière dans l'orthodoxie académique. Faut-il n'y voir qu'aveuglement religieux ? Sans doute, mais pas seulement... Originellement proposée en 1859, la théorie de l'évolution de Charles Darwin a profondément bouleversé la science et la société toute entière. Débarrassé de ses relents lamarckiens par August Weismann entre 1883 et 1888, le darwinisme, désormais qualifié de "néo-", s'est enrichi de la génétique de Gregor Mendel pour donner naissance en 1937, sous l'impulsion de Theodosius Dobzhansky, à la théorie synthétique de l'évolution. C'est dans cette incarnation "moderne" qu'il est devenu l'unique paradigme de la biologie contemporaine. Pourtant, loin des feux de la rampe, le couple infernal mutation/sélection ne satisfait pas tous les spécialistes. A quel point sa toute puissance peut-elle être mise en doute ? Dispose-t-on réellement de preuves de son efficacité, ou même tout simplement de son existence ? La diversité de la Vie sur Terre peut-elle s'expliquer par un principe aussi naïvement libéral ? C'est à ces questions et à quelques autres que nous tenterons de répondre au cours de cette conférence-débat, tout en tâchant de rester prudemment en dehors de toute considération métaphysique. Docteur en Sciences (Génétique Moléculaire Végétale), Denis BAURAIN est bioinformaticien à l'Université de Liège. Financées par le FNRS, ses recherches portent essentiellement sur l'histoire évolutive des premières cellules à noyau telle qu'on peut l'inférer à partir des séquences de gènes. [less ▲]

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