Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailIs dark matter made of mirror matter? Evidence from cosmological data
Ciarcelluti, Paolo; Wallemacq, Quentin ULg

in Physics Letters B (2014), 729

We present new fast numerical simulations of cosmic microwave background and large scale structure in the case in which the cosmological dark matter is made entirely or partly of mirror matter. We ... [more ▼]

We present new fast numerical simulations of cosmic microwave background and large scale structure in the case in which the cosmological dark matter is made entirely or partly of mirror matter. We consider scalar adiabatic primordial perturbations at linear scales in a flat Universe. The speed of the simulations allows us for the first time to use Markov Chain Monte Carlo analyses to constrain the mirror parameters. A Universe with pure mirror matter can fit very well the observations, equivalently to the case of an admixture with cold dark matter. In both cases, the analyses show a clear indication of the presence of a consistent amount of mirror dark matter, 0.05 < Ω_{mirror} h^2 < 0.12. [less ▲]

Detailed reference viewed: 39 (10 ULg)
Full Text
See detailStation de pompage de Jemeppe-sur-Meuse : suivi de forages et rapport de synthèse
Delvoie, Simon ULg; Collin, Frédéric ULg

Report (2014)

Suivi et analyse de neuf forages carottés réalisés à Jemeppe-sur-Meuse au sein de roches houillères. Les forages atteignent des cotes entre +35,00 et +31,00 m.

Detailed reference viewed: 11 (3 ULg)
See detailHors-cadres : des images qui manquent. Quand le documentaire ne peut pas tout montrer.
Hamers, Jérémy ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailTransnational modelling of the Meuse District with PegOpera simulation software
Grard, Aline ULg; Everbecq, Etienne ULg; MAGERMANS, POL ULg et al

in International Journal of River Basin Management (2014)

The environmental software PEGOPERA is a new tool resulting from the coupling of the PEGASE model (Planification Et Gestion de l’ASsainissement des Eaux, French acronym for planning and management of ... [more ▼]

The environmental software PEGOPERA is a new tool resulting from the coupling of the PEGASE model (Planification Et Gestion de l’ASsainissement des Eaux, French acronym for planning and management of water purification) with a friendly Graphical User Interface. PEGASE is an integrated and physically based river/basin model and is devoted to the characterisation of the physico-chemical state of surface water, at the scale of a whole watershed or basin, including International River Basin District (IRBD). The aim of the model is to simulate non stationary scenarios at various scales (from a few km² to hundreds of thousands km²) while handling the entire river tree (hundreds to thousands of water bodies). The purpose of PEGOPERA is to provide the stakeholders - as regards to surface water management - with a tool dedicated to the deterministic calculation of water quality of the rivers taking into account pollutant loads and discharges. In the context of the Water Framework Directive 2000/60/EC, the international coordination between neighbouring states and regions is required. The PEGOPERA software is adapted to simulate the IRBD Meuse. Indeed: i. An integrated transnational database relevant to the entire district is available; ii. The software is operational: the Meuse application has been calibrated and validated independently on most of regional sub-basins of the district; iii. The software could be used to simulate historical and future scenarios to assess water quality improvement that may be expected after applying basic and supplementary measures. The results demonstrate the relevance of the use of this software in this kind of transnational modelling. Some regions of the International District of the Meuse are validated on historical situations. Other parts still need to be improved in terms of consolidating the input databases. Prospective scenarios implementing measures from the WFD are carried out at this District scale. [less ▲]

Detailed reference viewed: 38 (26 ULg)
See detailLe rêve: la voie royale de la découverte freudienne de l'inconscient
Naziri, Despina ULg

Diverse speeche and writing (2014)

Detailed reference viewed: 15 (0 ULg)
Full Text
See detailOpinions, attitudes et comportements politiques. Tome 1. Notes provisoires
Grandjean, Geoffrey ULg

Learning material (2014)

Detailed reference viewed: 25 (5 ULg)
Full Text
Peer Reviewed
See detailCoastal flood damage and adaptation costs under 21st century sea-level rise
Hinkel, J.; Lincke, D.; Vafeidis, A. T. et al

in Proceedings of the National Academy of Sciences of the United States of America (2014), online

Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data ... [more ▼]

Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data, protection strategies, socioeconomic development and sea-level rise. Uncertainty in global mean and regional sea level was derived from four different climate models from the Coupled Model Intercomparison Project Phase 5, each combined with three land-ice scenarios based on the published range of contributions from ice sheets and glaciers. Without adaptation, 0.2–4.6% of global population is expected to be flooded annually in 2100 under 25–123 cm of global mean sea-level rise, with expected annual losses of 0.3–9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US$ 12–71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure. [less ▲]

Detailed reference viewed: 75 (10 ULg)
Full Text
See detailQuand le manuscrit devient tablette : préservation et exploitation d’un patrimoine culturel et universitaire à l’ère numérique
Simon, Stéphanie ULg

Conference given outside the academic context (2014)

Au cours de l'année 2013, le Réseau des Bibliothèques de l'ULg a pu réaliser la numérisation d'une cinquantaine de manuscrits exceptionnels issus de ses collections. Cette présentation replace ce projet ... [more ▼]

Au cours de l'année 2013, le Réseau des Bibliothèques de l'ULg a pu réaliser la numérisation d'une cinquantaine de manuscrits exceptionnels issus de ses collections. Cette présentation replace ce projet dans le cadre général de la numérisation du patrimoine et vous en détaille les différentes étapes. [less ▲]

Detailed reference viewed: 41 (9 ULg)
See detailPaleoenvironmental record of the Amik Basin (Amuq Plain, Southern Turkey) over the last 4000 years
Hubert, Aurelia ULg; El Ouahabi, Meriam ULg; Lebeau, Hélène ULg et al

Poster (2014, February 04)

Continous human occupation is attested in the Amik Basin since 6000-7000 BC. The low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. The Basin also is ... [more ▼]

Continous human occupation is attested in the Amik Basin since 6000-7000 BC. The low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to Turkey in the north. The study focuses on the sedimentary record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and assess possible human impact. The lake has been drained and progressively dried up since the mid-50s so that it is not watered during the summer season and constitutes a unique opportunity to collect sediment records. Sediments were collected at 1 cm to 2 cm intervals in a trench and in cores up to a depth of 5 meters in the clay deposits. A diverse array of complementary methods is applied to study the records: magnetic susceptibility, grain size, organic matter and inorganic carbon (L.O.I), XRD mineralogy, XRF geochemistry, carbon geochemistry. The age of the record is constrained combining radionuclide and radiocarbon dating. The record shows two intense phases of soil erosion with enrichments in Chromium and Nickel. The most recent erosion phase might be linked with enhanced development during the Roman and the growth of the Antioch City. The oldest one would occur around 3000 BC. The record also allows reconstructing past lake level variations and discusses the results in comparison with variations of the Dead Sea. [less ▲]

Detailed reference viewed: 30 (1 ULg)
See detailLes représentations de Synagoga aux portails occidentaux de la cathédrale d’Amiens : l’illustration de l’ « antijudaïsme » au lendemain de Latran IV ?
Lekane, Marie ULg

Conference (2014, February 04)

Les portails occidentaux amiénois sont munis de trois représentations de la Synagogue, sous la forme bien connue d’une personnification féminine aux yeux bandés. Deux scènes particulières, montrant la ... [more ▼]

Les portails occidentaux amiénois sont munis de trois représentations de la Synagogue, sous la forme bien connue d’une personnification féminine aux yeux bandés. Deux scènes particulières, montrant la Synagoga, se jouent sur des culots du portail de la Vierge, sous les pieds des Rois mages. Si l’une de ces scènes semble représenter le découronnement de la figure allégorique par le Christ, la seconde est plus énigmatique. Au portail du Jugement dernier, sous les pieds de l’archange Michel, se loge le couple antagoniste Ecclesia-Synagoga. La position éminemment négative de la Synagogue – sous le plateau démoniaque, à senestre du Christ, côtoyant le monde infernal – fait-elle écho aux récentes positions contre les Juifs prises et actées lors du Concile de Latran IV (1215) ? Afin de pouvoir amener des pistes de réflexions sur ces points, déjà soulevés par certains auteurs (W. Schlink, 1991), nous interrogerons les sources historiques sur la présence effective d’une communauté juive à Amiens et sur leurs conditions de vie. En outre, et plus généralement, nous analyserons les retombées tangibles des décisions prises lors du Concile de 1215, auquel participait Jean d’Abbeville, doyen de la cathédrale d’Amiens au moment de sa reconstruction, volontiers présenté comme « programmateur » de l’ensemble. Il est indispensable de reconsidérer soigneusement ces images et leurs composantes afin de définir leurs particularités et d’infirmer ou confirmer un « antijudaïsme » aux portails amiénois, ou du moins de pouvoir le caractériser. [less ▲]

Detailed reference viewed: 14 (3 ULg)
See detailMariage pour tous, homoparentalité
Naziri, Despina ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailHigh-frequency A-type pulsators discovered using SuperWASP
Holdsworth, Daniel L.; Smalley, B.; Gillon, Michaël ULg et al

in Monthly Notices of the Royal Astronomical Society (2014)

We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes ... [more ▼]

We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes greater than 0.5 millimagnitude. We identify over 350 stars which pulsate with periods less than 30 min. Spectroscopic follow-up of selected targets has enabled us to confirm 10 new rapidly oscillating Ap stars, 13 pulsating Am stars and the fastest known δ Scuti star. We also observe stars which show pulsations in both the high-frequency domain and the low-frequency δ Scuti range. This work shows the power of the WASP photometric survey to find variable stars with amplitudes well below the nominal photometric precision per observation. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
See detailWASP-20b and WASP-28b: a hot Saturn and a hot Jupiter in near-aligned orbits around solar-type stars
Anderson, D. R.; Collier Cameron, A.; Hellier, C. et al

E-print/Working paper (2014)

We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R ... [more ▼]

We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 $M_{\rm Jup}$; 1.46 $R_{\rm Jup}$) in a 4.9-day, near-aligned ($\lambda = 8.1 \pm 3.6^\circ$) orbit around CD-24 102 ($V$=10.7; F9). WASP-28b is an inflated, Jupiter-mass planet (0.91 $M_{\rm Jup}$; 1.21 $R_{\rm Jup}$) in a 3.4-day, near-aligned ($\lambda = 8 \pm 18^\circ$) orbit around a $V$=12, F8 star. As intermediate-mass planets in short orbits around aged, cool stars ($7^{+2}_{-1}$ Gyr for WASP-20 and $5^{+3}_{-2}$ Gyr for WASP-28; both with $T_{\rm eff}$ < 6250 K), their orbital alignment is consistent with the hypothesis that close-in giant planets are scattered into eccentric orbits with random alignments, which are then circularised and aligned with their stars' spins via tidal dissipation. [less ▲]

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailA multi-method approach to radial-velocity measurement for single-object spectra
David, M.; Blomme, R.; Frémat, Y. et al

in Astronomy and Astrophysics (2014), 562

Context. The derivation of radial velocities from large numbers of spectra that typically result from survey work, requires automation. However, except for the classical cases of slowly rotating late-type ... [more ▼]

Context. The derivation of radial velocities from large numbers of spectra that typically result from survey work, requires automation. However, except for the classical cases of slowly rotating late-type spectra, existing methods of measuring Doppler shifts require fine-tuning to avoid a loss of accuracy due to the idiosyncrasies of individual spectra. The radial velocity spectrometer (RVS) on the Gaia mission, which will start operating very soon, prompted a new attempt at creating a measurement pipeline to handle a wide variety of spectral types. <BR /> Aims: The present paper describes the theoretical background on which this software is based. However, apart from the assumption that only synthetic templates are used, we do not rely on any of the characteristics of this instrument, so our results should be relevant for most telescope-detector combinations. <BR /> Methods: We propose an approach based on the simultaneous use of several alternative measurement methods, each having its own merits and drawbacks, and conveying the spectral information in a different way, leading to different values for the measurement. A comparison or a combination of the various results either leads to a "best estimate" or indicates to the user that the observed spectrum is problematic and should be analysed manually. <BR /> Results: We selected three methods and analysed the relationships and differences between them from a unified point of view; with each method an appropriate estimator for the individual random error is chosen. We also develop a procedure for tackling the problem of template mismatch in a systematic way. Furthermore, we propose several tests for studying and comparing the performance of the various methods as a function of the atmospheric parameters of the observed objects. Finally, we describe a procedure for obtaining a knowledge-based combination of the various Doppler-shift measurements. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailAlignment in star-debris disc systems seen by Herschel
Greaves, J. S.; Kennedy, G. M.; Thureau, N. et al

in Monthly Notices of the Royal Astronomical Society : Letters (2014), 438

Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral ... [more ▼]

Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral types A-M where the stellar inclination is known and can be compared to that of the spatially resolved dust belts. The discs are found to be well aligned with the stellar equators, as in the case of the Sun's Kuiper belt, and unlike many close-in planets seen in transit surveys. The ensemble of stars here can be fitted with a star-disc tilt of ≲ 10°. These results suggest that proposed mechanisms for tilting the star or disc in fact operate rarely. A few systems also host imaged planets, whose orbits at tens of au are aligned with the debris discs, contrary to what might be expected in models where external perturbers induce tilts. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
See detailArchéologies de l'abstraction. Sur quelques récentes en philosophie des sciences
Cavazzini, Andrea ULg

Scientific conference (2014, February 01)

Detailed reference viewed: 10 (0 ULg)