Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailHow well can cold dark matter substructures account for the observed radio flux-ratio anomalies
Xu, Dandan; Sluse, Dominique ULg; Gao, Liang et al

in Monthly Notices of the Royal Astronomical Society (2015), 447

Discrepancies between the observed and model-predicted radio flux ratios are seen in a number of quadruply-lensed quasars. The most favoured interpretation of these anomalies is that cold dark matter (CDM ... [more ▼]

Discrepancies between the observed and model-predicted radio flux ratios are seen in a number of quadruply-lensed quasars. The most favoured interpretation of these anomalies is that cold dark matter (CDM) substructures present in lensing galaxies perturb the lens potentials and alter image magnifications and thus flux ratios. So far no consensus has emerged regarding whether or not the predicted CDM substructure abundance fully accounts for the lensing flux anomaly observations. Accurate modelling relies on a realistic lens sample in terms of both the lens environment and internal structures and substructures. In this paper, we construct samples of generalized and specific lens potentials, to which we add (rescaled) subhalo populations from the galaxy-scale Aquarius and the cluster-scale Phoenix simulation suites. We further investigate the lensing effects from subhaloes of masses several orders of magnitude below the simulation resolution limit. The resulting flux-ratio distributions are compared to the currently best available sample of radio lenses. The observed anomalies in B0128+437, B0712+472 and B1555+375 are more likely to be caused by propagation effects or oversimplified/improper lens modelling, signs of which are already seen in the data. Among the quadruple systems that have closely located image triplets/pairs, the anomalous flux ratios of MG0414+0534 can be reproduced by adding CDM subhaloes to its macroscopic lens potential, with a probability of 5-20 per cent; for B0712+472, B1422+231, B1555+375 and B2045+265, these probabilities are only of a few per cent. We hence find that CDM substructures are unlikely to be the whole reason for radio flux anomalies. We discuss other possible effects that might also be at work. [less ▲]

Detailed reference viewed: 16 (2 ULg)
Full Text
Peer Reviewed
See detailRotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
Wade, G. A.; Barbá, R. H.; Grunhut, J. et al

in Monthly Notices of the Royal Astronomical Society (2015), 447

We report magnetic and spectroscopic observations and modelling of the Of?p star CPD -28° 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic ... [more ▼]

We report magnetic and spectroscopic observations and modelling of the Of?p star CPD -28° 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic spectra of photospheric and wind-sensitive spectral lines. A period search results in an unambiguous 73.41 d variability period. High-resolution spectropolarimetric data analysed using least-squares deconvolution yield a Zeeman signature detected in the mean Stokes V profile corresponding to phase 0.5 of the spectral ephemeris. Interpreting the 73.41 d period as the stellar rotational period, we have phased the equivalent widths and inferred longitudinal field measurements. The phased magnetic data exhibit a weak sinusoidal variation, with maximum of about 565 G at phase 0.5, and a minimum of about -335 G at phase 0.0, with extrema approximately in phase with the (double-wave) Hα equivalent width variation. Modelling of the Hα equivalent width variation assuming a quasi-3D magnetospheric model produces a unique solution for the ambiguous couplet of inclination and magnetic obliquity angles: (i, β) or (β, i) = (35°, 90°). Adopting either geometry, the longitudinal field variation yields a dipole polar intensity B[SUB]d[/SUB] = 2.6 ± 0.9 kG, consistent with that obtained from direct modelling of the Stokes V profiles. We derive a wind magnetic confinement parameter η[SUB]*[/SUB] ≃ 100, leading to an Alfvén radius R[SUB]A[/SUB] ≃ 3-5R[SUB]*[/SUB], and a Kepler radius R[SUB]K[/SUB] ≃ 20R[SUB]*[/SUB]. This supports a physical scenario in which the Hα emission and other line variability have their origin in an oblique, corotating `dynamical magnetosphere' structure resulting from a magnetically channelled wind. Nevertheless, the details of the formation of spectral lines and their variability within this framework remain generally poorly understood. [less ▲]

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
See detailThe small binary asteroid (939) Isberga
Carry, B.; Matter, A.; Scheirich, P. et al

in Icarus (2015), 248

In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here at characterizing the surface composition, mutual orbit, size, mass ... [more ▼]

In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here at characterizing the surface composition, mutual orbit, size, mass, and density of the small main-belt binary asteroid (939) Isberga. For that, we conduct a suite of multi-technique observations, including optical lightcurves over many epochs, near-infrared spectroscopy, and interferometry in the thermal infrared. We develop a simple geometric model of binary systems to analyze the interferometric data in combination with the results of the lightcurve modeling. From spectroscopy, we classify Ibserga as a Sq-type asteroid, consistent with the albedo of 0.14<SUB>-0.06</SUB><SUP>+0.09</SUP> (all uncertainties are reported as 3-σ range) we determine (average albedo of S-types is 0.197 ± 0.153, see Pravec et al. (Pravec et al. [2012]. Icarus 221, 365-387). Lightcurve analysis reveals that the mutual orbit has a period of 26.6304 ± 0.0001 h, is close to circular (eccentricity lower than 0.1), and has pole coordinates within 7° of (225°, +86°) in Ecliptic J2000, implying a low obliquity of 1.5<SUB>-1.5</SUB><SUP>+6.0</SUP> deg . The combined analysis of lightcurves and interferometric data allows us to determine the dimension of the system and we find volume-equivalent diameters of 12.4<SUB>-1.2</SUB><SUP>+2.5</SUP> km and 3.6<SUB>-0.3</SUB><SUP>+0.7</SUP> km for Isberga and its satellite, circling each other on a 33 km wide orbit. Their density is assumed equal and found to be 2.91<SUB>-2.01</SUB><SUP>+1.72</SUP> gcm<SUP>-3</SUP> , lower than that of the associated ordinary chondrite meteorites, suggesting the presence of some macroporosity, but typical of S-types of the same size range (Carry [2012]. Planet. Space Sci. 73, 98-118). The present study is the first direct measurement of the size of a small main-belt binary. Although the interferometric observations of Isberga are at the edge of MIDI capabilities, the method described here is applicable to others suites of instruments (e.g., LBT, ALMA). [less ▲]

Detailed reference viewed: 15 (0 ULg)
Peer Reviewed
See detailCan the exploration of left space be induced implicitly in unilateral neglect?
Wansard, Murielle ULg; Bartolomeo, Paolo; Vanderaspoilden, Valérie et al

Poster (2015, March)

The purpose of the present study was to explore the ability of neglect patients to detect and exploit the predictive value of a cue to respond more quickly and accurately to targets on their ... [more ▼]

The purpose of the present study was to explore the ability of neglect patients to detect and exploit the predictive value of a cue to respond more quickly and accurately to targets on their contralesional side in a Posner spatial cueing task. The majority of the cues (i.e. 80%) were invalid, indicating that the target would appear on the opposite side, although patients were not informed of this bias. Our results demonstrate that some neglect patients were able to extract the cue’s predictability and use it to orient faster toward the left. This cueing effect was present even in patients who were subsequently unable to describe the predictive character of the cues, and thus was not modulated by reportable awareness of the cue-target relation. [less ▲]

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailData in support of metabolic reprogramming in transformed mouse cortical astrocytes: A proteomic study
Bentaib, Azeddine; De Tullio, Pascal ULg; Chneiweiss, Hervé et al

in Data in Brief (2015), 2(0), 1-5

2D-DIGE analysis coupled with mass spectrometry is a global, without a priori, comparative proteomic approach particularly suited to identify and quantify enzymes isoforms and structural proteins, thus ... [more ▼]

2D-DIGE analysis coupled with mass spectrometry is a global, without a priori, comparative proteomic approach particularly suited to identify and quantify enzymes isoforms and structural proteins, thus making it an efficient tool for the characterization of the changes in cell phenotypes that occur in physiological and pathological conditions. In this data article in support of the research article entitled “Metabolic reprogramming in transformed mouse cortical astrocytes: a proteomic study” [1] we illustrate the changes in protein profile that occur during the metabolic reprogramming undergone by cultured mouse astrocytes in a model of in-vitro cancerous transformation [2]. [less ▲]

Detailed reference viewed: 27 (2 ULg)
Full Text
Peer Reviewed
See detailBaryon resonances in large Nc QCD
Matagne, Nicolas; Stancu, Floarea ULg

in Reviews of Modern Physics (2015)

We review the current status and present open challenges of large $N_c$ QCD baryon spectroscopy. After introducing the $1/N_c$ expansion method we first shortly revisit the latest achievements for the ... [more ▼]

We review the current status and present open challenges of large $N_c$ QCD baryon spectroscopy. After introducing the $1/N_c$ expansion method we first shortly revisit the latest achievements for the ground state properties. Next we discuss the applicability of this method to excited states, presenting two different approaches with their advantages and disadvantages. Selected results for the spectrum and strong and electromagnetic decays are described. We also present further developments for the applicability of the method to excited states, based on the qualitative compatibility between the quark excitation picture and the meson-nucleon scattering picture. We show that a quantitative comparison between results obtained from the mass formula of the $1/N_c$ expansion method and quark models brings convincing support to quark models and shortly discuss the implications of different large $N_c$ limits. We stress that the SU(6) spin-flavor structure of large $N_c$ baryon allows a convenient classification of highly excited resonances into SU(3) multiplets and predicts mass ranges for the missing partners. [less ▲]

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailLes valeurs et les valorisations des images
Dondero, Maria Giulia ULg

in Biglari, Amir; Lopes, Iva (Eds.) Les valeurs. Aux fondements de la sémiotique (2015)

Cet article vise à explorer la manière dont la sémiotique greimassienne a traité la question des valeurs dans le cadre de l’image, notamment photographique et artistique. Après une relecture critique de ... [more ▼]

Cet article vise à explorer la manière dont la sémiotique greimassienne a traité la question des valeurs dans le cadre de l’image, notamment photographique et artistique. Après une relecture critique de l’ouvrage de Jean-Marie Floch, Les formes de l’empreinte, et de la distinction entre valeurs dans l’image et valorisations des images, ce travail se consacre à l’exposition de nouvelles propositions de la sémiotique des pratiques de Jacques Fontanille en essayant de les lier à des réflexions sur les objets et les pratiques de la photographie artistique (l’utilisation des séries, de l’original, des différents tirages, etc.). Si l’attention est portée surtout sur la photo artistique, ce texte envisage également une comparaison avec les pratiques de l’original et de l’authenticité dans la photo de guerre, la photo de famille et la photo-image pieuse. L’objectif majeur de ce travail est d’étudier les diverses pratiques de valorisation des images photographiques afin de faire éclater la notion ontologique de trace photographique. [less ▲]

Detailed reference viewed: 26 (5 ULg)
Full Text
Peer Reviewed
See detailLes forces de la négation dans l’image
Dondero, Maria Giulia ULg

in Acquarelli, Luca (Ed.) Au prisme du figural. Le sens des images entre forme et force (2015)

Ce texte vise à décrire un type particulier de forces inhérentes à la configuration de l’image. Il s’agit de forces qui mettent en crise la figuration et le caractère affirmatif de l’image, en les ... [more ▼]

Ce texte vise à décrire un type particulier de forces inhérentes à la configuration de l’image. Il s’agit de forces qui mettent en crise la figuration et le caractère affirmatif de l’image, en les détournant et en les rendant « hésitants ». Nous souhaitons démontrer que l’image n’est pas contrainte d’affirmer ce qu’elle met en scène : elle a également la capacité de le nier. La négation par l’image représente à nos yeux un défi majeur pour les sémioticiens du visuel et les théoriciens de l’art, notamment dans le cadre de recherches sur le langage de l’image, le métalangage visuel et, plus généralement, sur les capacités de l’image à développer un discours autonome par rapport au discours verbal [less ▲]

Detailed reference viewed: 25 (3 ULg)
Full Text
Peer Reviewed
See detailAzione, testualizzazione, notazione
Dondero, Maria Giulia ULg

in Espressione e contenuto. Rivista on-line dell'AISS Associazione Italiana di Studi Semiotici (2015, March)

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailDoes the production of Belgian bioethanol fit with European requirements on GHG emissions? Case of wheat
Belboom, Sandra ULg; Bodson, Bernard ULg; Léonard, Angélique ULg

in Biomass & Bioenergy (2015), 74

This paper undertakes an environmental evaluation of bioethanol production, using wheat cultivated in Belgium. Cultivation steps are modelled using Belgian specific data. Wheat transformation in ethanol ... [more ▼]

This paper undertakes an environmental evaluation of bioethanol production, using wheat cultivated in Belgium. Cultivation steps are modelled using Belgian specific data. Wheat transformation in ethanol relies on industrial data. GHG emissions of the whole life cycle are calculated and compared with the default values given by the European Renewable Energy Directive. Belgian wheat bioethanol achieves a 5% higher GHG reduction than the one mentioned in the European directive but impact repartition is different with a higher importance of cultivation step in our case. Belgian wheat bioethanol complies with the current sustainability criteria but is also able to conform to further ones. Sensitivity analyses are performed on the importance of N fertilizers and associated emissions known as main important parameters. These analyses reveal non negligible variations and then a range of available GHG reduction when using wheat bioethanol. [less ▲]

Detailed reference viewed: 11 (2 ULg)
Full Text
Peer Reviewed
See detailWhat is important in being cured from: Does discordance between physicians and patients matter? (2)
Demyttenaere, Koen; Donneau, Anne-Françoise ULg; Albert, Adelin ULg et al

in Journal of Affective Disorders (2015), 174(2015), 372-377

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailWhat is important in being cured from depression? Discordance between physicians and patients (1)
Demyttenaere, Koen; Donneau, Anne-Françoise ULg; Albert, Adelin ULg et al

in Journal of Affective Disorders (2015), 174(2015), 390-396

Detailed reference viewed: 7 (0 ULg)
Peer Reviewed
See detailWheat yield sensitivity to climate change across a European transect for a large ensemble of crop models
Pirttioja, Nina; Carter, Timothy; Fronzek, Stefan et al

in Soussana, Jean-Francois (Ed.) Proceedings of the Climate Smart Agriculture 2015 conference (2015, March)

Detailed reference viewed: 17 (1 ULg)
Peer Reviewed
See detailEffects of transcranial magnetic stimulation coil orientation and pulse width on short-latency afferent inhibition
Hannah, Ricci; D'Ostilio, Kevin ULg; Goetz, Stefan et al

Poster (2015, March)

Detailed reference viewed: 8 (1 ULg)
Full Text
See detailPreliminary analysis of Martian dayglow observed by the Imaging Ultraviolet Spectrograph onboard MAVEN
Jain, Sonal; Stewart, Ian; Schneider, Nick et al

Conference (2015, March)

Detailed reference viewed: 18 (0 ULg)
Full Text
See detailPreliminary analysis of Martian nightglow and aurora observed by MAVEN's Imaging UltraViolet Spectrograph
Stiepen, Arnaud ULg; Stewart; Jain et al

Conference (2015, March)

Detailed reference viewed: 14 (0 ULg)