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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 ▲]

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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 ▲]

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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 ▲]

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See detailSpectroscopic variability of two Oe stars
Rauw, Grégor ULg; Morel, Thierry ULg; Nazé, Yaël ULg et al

in Astronomy and Astrophysics (2015), 575

Context. The two Oe stars HD 45 314 and HD 60 848 have recently been found to exhibit very different X-ray properties: whilst HD 60 848 has an X-ray spectrum and the emission level typical of most OB ... [more ▼]

Context. The two Oe stars HD 45 314 and HD 60 848 have recently been found to exhibit very different X-ray properties: whilst HD 60 848 has an X-ray spectrum and the emission level typical of most OB stars, HD 45 314 features a much harder and brighter X-ray emission, making it a so-called γ Cas analogue. Aims: Monitoring the optical spectra could provide hints towards the origin of these very different behaviours. Methods: We analyse a large set of spectroscopic observations of HD 45 314 and HD 60 848, extending over 20 years. We further attempt to fit the Hα line profiles of both stars with a simple model of emission line formation in a Keplerian disk. Results: Strong variations in the strengths of the Hα, Hβ, and He i λ 5876 emission lines are observed for both stars. In the case of HD 60 848, we find a time lag between the variations in the equivalent widths of these lines, which is currently not understood. The emission lines are double peaked with nearly identical strengths of the violet and red peaks. The Hα profile of this star can be successfully reproduced by our model of a disk seen under an inclination of 30°. In the case of HD 45 314, the emission lines are highly asymmetric and display strong line profile variations. We find a major change in behaviour between the 2002 outburst and the one observed in 2013. This concerns both the relationship between the equivalent widths of the various lines and their morphologies at maximum strength (double-peaked in 2002 versus single-peaked in 2013). Our simple disk model fails to reproduce the observed Hα line profiles of HD 45 314. Conclusions: Our results further support the interpretation that Oe stars do have decretion disks similar to those of Be stars. Whilst the emission lines of HD 60 848 are explained well by a disk with a Keplerian velocity field, the disk of HD 45 314 seems to have a significantly more complex velocity field that could be another signature of the phenomenon that produces its peculiar X-ray emission. [less ▲]

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See detailSearch for magnetic fields in particle-accelerating colliding-wind binaries
Neiner, C.; Grunhut, J.; Leroy, B. et al

in Astronomy and Astrophysics (2015), 575

Some colliding-wind massive binaries, called particle-accelerating colliding-wind binaries (PACWB), exhibit synchrotron radio emission, which is assumed to be generated by a stellar magnetic field ... [more ▼]

Some colliding-wind massive binaries, called particle-accelerating colliding-wind binaries (PACWB), exhibit synchrotron radio emission, which is assumed to be generated by a stellar magnetic field. However, no measurement of magnetic fields in these stars has ever been performed. We aim at quantifying the possible stellar magnetic fields present in PACWB to provide constraints for models. We gathered 21 high-resolution spectropolarimetric observations of 9 PACWB available in the ESPaDOnS, Narval and HarpsPol archives. We analysed these observations with the least squares deconvolution method. We separated the binary spectral components when possible. No magnetic signature is detected in any of the 9 PACWB stars and all longitudinal field measurements are compatible with 0 G. We derived the upper field strength of a possible field that could have remained hidden in the noise of the data. While the data are not very constraining for some stars, for several stars we could derive an upper limit of the polar field strength of the order of 200 G. We can therefore exclude the presence of strong or moderate stellar magnetic fields in PACWB, typical of the ones present in magnetic massive stars. Weak magnetic fields could however be present in these objects. These observational results provide the first quantitative constraints for future models of PACWB. [less ▲]

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See detailLe "champ" de l'accompagnement des demandeurs d'emploi est-il un "marché" ?
Remy, Céline ULg

in Galabov, Antoniy; Rouet, Gilles (Eds.) Services publics, entreprises publiques : quelle place pour les citoyens? (2015, March 01)

Le but de ce chapitre est d’interroger le champ de l’accompagnement des demandeurs d’emploi comme étant ou non un marché conventionnel. Pour ce faire, les concepts de marché, de quasi-marché, de marché ... [more ▼]

Le but de ce chapitre est d’interroger le champ de l’accompagnement des demandeurs d’emploi comme étant ou non un marché conventionnel. Pour ce faire, les concepts de marché, de quasi-marché, de marché public et de champ sont clarifiés dans un premier temps. Pour comprendre le fonctionnement du marché de l’accompagnement, il est nécessaire dans un deuxième temps d’examiner quatre dimensions qui sont le périmètre et le financement de celui-ci mais également la sélection des opérateurs externes par les services publics de l’emploi et les stratégies développées par les différents acteurs appartenant à ce marché. L’étude de ces dimensions qui s’appuie sur trois études de cas permet de montrer la singularité du marché de l’accompagnement. [less ▲]

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See detailModification of standard ISHAGE methodology for CD34+ cells count on thawed Cord Blood Units: results from a multi-center Eurocord/Netcord study
Saccardi, RICCARDO; Azqueta, C; Ballerini, C et al

in Bone Marrow Transplantation (2015), 50

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See detailGestion implantaire de l'édentement unitaire dans le secteur esthétique : une approche visant à optimiser les tissus. Partie I : aspect chirurgical
LAMBERT, France ULg

in Réalites Cliniques : Revue Européenne d'Odontologie (2015), 26(n°1),

Nous sommes tous bien conscients de la problématique liée au remodelage osseux après extraction dentaire, en particulier dans la zone esthétique. Les conséquences cliniques sont telles que le recours à ... [more ▼]

Nous sommes tous bien conscients de la problématique liée au remodelage osseux après extraction dentaire, en particulier dans la zone esthétique. Les conséquences cliniques sont telles que le recours à des techniques de régénération tissulaire est souvent nécéssaire pour la pose de l'implant et pour assurer des résultats esthétiques. Cet article vise à démontrer l'efficacité d'un protocole d'optimisation tissulaire basé sur la préservation du capital osseux et sur l'optimisation des tissus gingivaux lors d'une extraction dentaire dans la zone esthétique. L'objectif de cet article est de suggérer un processus décisionnel en matière de technique chirurgicale, reposant d'une part sur l'examen clinique initial et, d'autre part, sur une excellente compréhension du concept biologique. [less ▲]

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See detailNetworks of prospective thoughts: the organizational role of emotion and its impact on well-being
Demblon, Julie ULg; D'Argembeau, Arnaud ULg

in Cognition & Emotion (2015)

Recent research has shown that many prospective thoughts are organised in networks of related events, but the relational dimensions that contribute to the formation of such networks are not fully ... [more ▼]

Recent research has shown that many prospective thoughts are organised in networks of related events, but the relational dimensions that contribute to the formation of such networks are not fully understood. Here, we investigated the organisational role of emotion by using cues of different valence for eliciting event networks. We found that manipulating the emotional valence of cues influenced the characteristics of events within networks, and that members of a network were more similar to each other on affective components than they were to members of other networks. Furthermore, a substantial proportion of events within networks were part of thematic clusters and cluster membership significantly modulated the impact of represented events on current well-being, in part through an intensification of the emotion felt when thinking about these events. These findings demonstrate that emotion contributes to the organisation of future thoughts in networks that can affect people’s well-being. [less ▲]

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See detailThe role of sea ice in the carbon cycle of Polar Seas: 1D to 3D modelling
Moreau, S.; Vancoppenolle, M.; Delille, Bruno ULg et al

Poster (2015, March)

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See detailQuand les maths nous transportent...
Crama, Yves ULg

Conference given outside the academic context (2015)

Voici trois siècles, il se racontait dans la ville prussienne de Königsberg qu’un promeneur ne pouvait pas traverser successivement les sept ponts reliant les différentes parties de la cité sans emprunter ... [more ▼]

Voici trois siècles, il se racontait dans la ville prussienne de Königsberg qu’un promeneur ne pouvait pas traverser successivement les sept ponts reliant les différentes parties de la cité sans emprunter deux fois le même pont. Leonhard Euler apporta en 1736 une démonstration élégante de cette affirmation. Il produisit ainsi l’une des premières applications des mathématiques à la construction d’itinéraires optimisés. Aujourd’hui, la modélisation mathématique est devenue un outil indispensable pour les décideurs dans le monde du transport et, plus généralement, pour la gestion et la planification des activités logistiques. Qu’il s’agisse de calculer l’itinéraire le plus rapide de Liège à Marbella, d’optimiser les tournées de livraison d’une chaîne de grande distribution, de charger des navires ou des avions en assurant leur stabilité, de réduire les stocks excédentaires d’une entreprise pharmaceutique, de fixer le prix de billets de TGV en fonction des places disponibles, dans chaque cas, les mathématiques, alliées à l’informatique, permettent de formuler de façon précise le problème rencontré et d’y apporter des réponses pertinentes. Cet exposé présentera quelques applications typiques des mathématiques dans le domaine de la logistique et fournira un aperçu des méthodes qui y sont mises en œuvre. [less ▲]

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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 ▲]

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See detailBlue sky and green bugs – How physical parameters and algal speciation influence DMSP and DMS profiles in Antarctic winter sea ice
Uhlig, C.; Rintala, J.-M.; Tison, J.-L. et al

Poster (2015, March)

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See detailEvaluation des actions transversales du New Deal bruxellois
Cipriano, Sabrine; Fallon, Catherine ULg; Fastré, Perrine et al

in Les Cahiers de l'IBSA (2015), 4

En vue d’assurer la cohérence de la politique de l’emploi sur le territoire bruxellois, le volet transversal du « Pacte de Croissance Urbaine Durable », appelé aussi « New Deal » bruxellois, inventorie ... [more ▼]

En vue d’assurer la cohérence de la politique de l’emploi sur le territoire bruxellois, le volet transversal du « Pacte de Croissance Urbaine Durable », appelé aussi « New Deal » bruxellois, inventorie une série d’actions à mettre en œuvre de manière coordonnée. Pour cela, il définit un cadre permettant de développer des partenariats entre acteurs aussi différents que des administrations, des partenaires sociaux ou encore des cabinets ministériels, dépendant d’institutions tantôt régionales, tantôt communautaires, francophones ou néerlandophones. Il repense ainsi l’organisation de la coordination entre ces acteurs, sans pour autant toucher à la répartition institutionnelle des compétences sur le territoire bruxellois. L’évaluation présentée dans ce Cahier de l’IBSA livre un bilan de l’utilité de ces dispositifs de coordination, selon le point de vue des acteurs impliqués. Elle repose sur une comparaison de huit études de cas qui portent sur une période d’observation de trois ans, allant d’avril 2011 à mars 2014. L’évaluation met en lumière la nouvelle méthode de travail du New Deal qui permet, via des collaborations croisées, de dépasser certaines fragmentations politiques et institutionnelles autour de la question de l’emploi sur le territoire bruxellois. [less ▲]

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See detailHow snow affects air-sea ice CO2 fluxes ?
Delille, Bruno ULg; Kotovitch, Marie ULg; Van Der Linden, Fanny ULg et al

Poster (2015, March)

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See detailPhotosynthesis-irradiance response curves revealed active sympagic communities in the Weddell Sea Winter, 2013
Rintala, J.-M.; Luhtanen, A.-M.; Enberg, S. et al

Poster (2015, March)

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See detailELICITOR SCREENING TO PROTECT WINTER WHEAT AGAINST ZYMOSEPTORIA TRITICI BLOTCH
Le Mire, Géraldine ULg; Siah, Ali; Jijakli, Haissam ULg

Poster (2015, March)

Plant protection strategies are strongly focused today on the development of alternative methods in order to complete or replace conventional chemical inputs. Elicitors of biological origin are ... [more ▼]

Plant protection strategies are strongly focused today on the development of alternative methods in order to complete or replace conventional chemical inputs. Elicitors of biological origin are increasingly considered as a promising tool as biocontrol agents. They offer the possibility, through the induction of plant natural defences, to preventively protect plants against a large spectra of diseases. Multiple elicitors have already been identified since their first discovery in the late 70s, but few research has been focused on crop pathogens although such diseases can strongly impact both yield and grain quality. We describe hereby a method of elicitor screening to protect wheat against Zymoseptoria tritici. Focus is made on the importance of a good disease infection protocol in order to achieve screening tests. [less ▲]

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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 ▲]

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