Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailLens galaxies in the Illustris simulation: power-law models and the bias of the Hubble constant from time delays
Xu, Dandan; Sluse, Dominique ULg; Schneider, Peter et al

in Monthly Notices of the Royal Astronomical Society (2016), 456

A power-law density model, i.e. ρ (r) ∝ r^{-γ ^' }}, has been commonly employed in strong gravitational lensing studies, including the so-called time-delay technique used to infer the Hubble constant H ... [more ▼]

A power-law density model, i.e. ρ (r) ∝ r^{-γ ^' }}, has been commonly employed in strong gravitational lensing studies, including the so-called time-delay technique used to infer the Hubble constant H[SUB]0[/SUB]. However, since the radial scale at which strong lensing features are formed corresponds to the transition from the dominance of baryonic matter to dark matter, there is no known reason why galaxies should follow a power law in density. The assumption of a power law artificially breaks the mass-sheet degeneracy, a well-known invariance transformation in gravitational lensing which affects the product of Hubble constant and time delay and can therefore cause a bias in the determination of H[SUB]0[/SUB] from the time-delay technique. In this paper, we use the Illustris hydrodynamical simulations to estimate the amplitude of this bias, and to understand how it is related to observational properties of galaxies. Investigating a large sample of Illustris galaxies that have velocity dispersion σ[SUB]SIE[/SUB] ≥ 160 km s[SUP]-1[/SUP] at redshifts below z = 1, we find that the bias on H[SUB]0[/SUB] introduced by the power-law assumption can reach 20-50 per cent, with a scatter of 10-30 per cent (rms). However, we find that by selecting galaxies with an inferred power-law model slope close to isothermal, it is possible to reduce the bias on H[SUB]0[/SUB] to ≲ 5 per cent and the scatter to ≲ 10 per cent. This could potentially be used to form less biased statistical samples for H[SUB]0[/SUB] measurements in the upcoming large survey era. [less ▲]

Detailed reference viewed: 20 (2 ULg)
See detailTwo Small Temperate Planets Transiting Nearby M Dwarfs in K2 Campaigns 0 and 1
Schlieder, Joshua E.; Crossfield, Ian J. M.; Petigura, Erik A. et al

in Astrophysical Journal (2016), 818

The prime Kepler mission revealed that small planets (<4 {R}[SUB]\oplus [/SUB]) are common, especially around low-mass M dwarfs. K2, the repurposed Kepler mission, continues this exploration of small ... [more ▼]

The prime Kepler mission revealed that small planets (<4 {R}[SUB]\oplus [/SUB]) are common, especially around low-mass M dwarfs. K2, the repurposed Kepler mission, continues this exploration of small planets around small stars. Here we combine K2 photometry with spectroscopy, adaptive optics imaging, and archival survey images to analyze two small planets orbiting the nearby field-age M dwarfs, K2-26 (EPIC 202083828) and K2-9. K2-26 is an {{M}}1.0+/- 0.5 dwarf at 93 ± 7 pc from K2 Campaign 0. We validate its planet with a day period of 14.5665 and estimate a radius of {2.67}[SUB]-0.42[/SUB][SUP]+0.46[/SUP] {R}[SUB]\oplus [/SUB]. K2-9 is an {{M}}2.5+/- 0.5 dwarf at 110 ± 12 pc from K2 Campaign 1. K2-9b was first identified by Montet et al.; here we present spectra and adaptive optics imaging of the host star and independently validate and characterize the planet. Our analyses indicate K2-9b is a {2.25}[SUB]-0.96[/SUB][SUP]+0.53[/SUP] {R}[SUB]\oplus [/SUB] planet with a 18.4498 day period. K2-26b exhibits a transit duration that is too long to be consistent with a circular orbit given its measured stellar radius. Thus, the long transits are likely due to the photoeccentric effect and our transit fits hint at an eccentric orbit. Both planets receive low incident flux from their host stars and have estimated equilibrium temperatures <500 K. K2-9b may receive approximately Earth-like insolation. However, its host star exhibits strong GALEX UV emission which could affect any atmosphere it harbors. K2-26b and K2-9b are representatives of a poorly studied class of small planets with cool temperatures that have radii intermediate to Earth and Neptune. Future study of these systems can provide key insight into trends in bulk composition and atmospheric properties at the transition from silicate dominated to volatile rich bodies. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, La Silla Observatory, Chile during program ID 194.C-0443. [less ▲]

Detailed reference viewed: 11 (2 ULg)
Full Text
Peer Reviewed
See detailThe LEECH Exoplanet Imaging Survey: Characterization of the Coldest Directly Imaged Exoplanet, GJ 504 b, and Evidence for Superstellar Metallicity
Skemer, Andrew J.; Morley, Caroline V.; Zimmerman, Neil T. et al

in Astrophysical Journal (2016), 817

As gas giant planets and brown dwarfs radiate away the residual heat from their formation, they cool through a spectral type transition from L to T, which encompasses the dissipation of cloud opacity and ... [more ▼]

As gas giant planets and brown dwarfs radiate away the residual heat from their formation, they cool through a spectral type transition from L to T, which encompasses the dissipation of cloud opacity and the appearance of strong methane absorption. While there are hundreds of known T-type brown dwarfs, the first generation of directly imaged exoplanets were all L type. Recently, Kuzuhara et al. announced the discovery of GJ 504 b, the first T dwarf exoplanet. GJ 504 b provides a unique opportunity to study the atmosphere of a new type of exoplanet with a ˜500 K temperature that bridges the gap between the first directly imaged planets (˜1000 K) and our own solar system's Jupiter (˜130 K). We observed GJ 504 b in three narrow L-band filters (3.71, 3.88, and 4.00 μm), spanning the red end of the broad methane fundamental absorption feature (3.3 μm) as part of the LBTI Exozodi Exoplanet Common Hunt (LEECH) exoplanet imaging survey. By comparing our new photometry and literature photometry with a grid of custom model atmospheres, we were able to fit GJ 504 b's unusual spectral energy distribution for the first time. We find that GJ 504 b is well fit by models with the following parameters: T[SUB]eff[/SUB] = 544 ± 10 K, g < 600 m s[SUP]-2[/SUP], [M/H] = 0.60 ± 0.12, cloud opacity parameter of f[SUB]sed[/SUB] = 2-5, R = 0.96 ± 0.07 R[SUB]Jup[/SUB], and log(L) = -6.13 ± 0.03 L[SUB]⊙[/SUB], implying a hot start mass of 3-30 M[SUB]jup[/SUB] for a conservative age range of 0.1-6.5 Gyr. Of particular interest, our model fits suggest that GJ 504 b has a superstellar metallicity. Since planet formation can create objects with nonstellar metallicities, while binary star formation cannot, this result suggests that GJ 504 b formed like a planet, not like a binary companion. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrophisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and the Research Corporation, on behalf of the University of Notre Dame, University of Minnesota, and University of Virginia. [less ▲]

Detailed reference viewed: 16 (1 ULg)
Full Text
See detailResidual tumor micro-foci and overwhelming regulatory T lymphocyte infiltration are the causes of bladder cancer recurrence.
Parodi, Alessia; Traverso, Paolo; Kalli, Francesca et al

in Oncotarget (2016), 7(6), 6424-6435

Bladder cancer has an unexplained, high recurrence rate. Causes of recurrence might include the presence of sporadic tumor micro-foci in the residual urothelial tissue after surgery associated with an ... [more ▼]

Bladder cancer has an unexplained, high recurrence rate. Causes of recurrence might include the presence of sporadic tumor micro-foci in the residual urothelial tissue after surgery associated with an inverted ratio between intratumoral effector and regulatory T cell subsets. Hence, surgical specimens of both tumors and autologous, macroscopically/histologically free-of-tumor tissues were collected from 28 and 20 patients affected by bladder or renal cancer, respectively. The frequencies of effector (IFNγ+ and IL17+ T cells) and regulatory (CD4+CD25hiCD127lo and CD8+CD28-CD127loCD39+ Treg) T cell subpopulations among tumor infiltrating lymphocytes were analyzed by immunofluorescence, while the gene expression of MAGE-A1 and MAGE-A2 tumor-associated antigens was studied by RT-PCR. The results show that both the T cell infiltrate and the frequency of MAGE-A1/A2 gene expression were comparable in tumors and in autologous free-of-tumor tissues in bladder cancer, while the autologous free-of-tumor renal tissues showed reduced T cell infiltrate and frequency of MAGE gene expression as compared to the autologous tumors. Importantly, the intra-tumor T effector/Treg cell ratio was consistently <1 in bladder cancer patients (n. 7) who relapsed within two years, while it was always >1 in patients (n. 6) without recurrence (regardless of tumor stage) (P = 0.0006, Odds ratio = 195). These unprecedented findings clarify the pathogenic mechanism of bladder cancer recurrence and suggest that microscopically undetectable micro-foci of tumor may predispose to recurrence when associated with an inverted intratumoral T effector/Treg cell ratio. [less ▲]

Detailed reference viewed: 83 (1 ULg)
Full Text
Peer Reviewed
See detailSubstituted azafluorenones: access from dihalogeno diaryl ketones by palladium-catalyzed auto-tandem processes and evaluation of their antibacterial, antifungal, antimalarial and antiproliferative activities
Marquise, Nada; Chevallier, Floris; Nassar, Ekhlas et al

in Tetrahedron (2016), 72(6), 825-836

Substituted azafluorenones were synthesized from dihalogeno diaryl ketones under palladium catalysis by combining, in auto-tandem processes, Suzuki coupling and intramolecular arylation reactions ... [more ▼]

Substituted azafluorenones were synthesized from dihalogeno diaryl ketones under palladium catalysis by combining, in auto-tandem processes, Suzuki coupling and intramolecular arylation reactions. Different dihalogenated diaryl ketones, prepared by sequential deprotocupration-aroylation, were identified as suitable substrates to this purpose. Conditions were identified to allow successful syntheses of several 6-/7-arylated 4-azafluorenones, 1-substituted 4-azafluorenones, 2-phenyl-3-azafluorenone, and 4-phenyl-3-azafluorenone from 3-(bromobenzoyl)-2-chloropyridines, 3-benzoyl-4-bromo-2-chloropyridines, 4-benzoyl-2,5-dichloropyridine, and 4-benzoyl-2,3-dichloropyridine, respectively. Some of the synthesized compounds exhibit interesting biological properties [less ▲]

Detailed reference viewed: 25 (11 ULg)
Full Text
Peer Reviewed
See detailComputed Tomography and Magnetic Resonance Findings in Athletes at Risk for Sudden Cardiac Death
Ghekiere, Olivier; Nchimi Longang, Alain ULg; Bijnens, Eric et al

in Journal of the Belgian Society of Radiology (2016, February), 1

Detailed reference viewed: 19 (1 ULg)
Full Text
Peer Reviewed
See detailNumerical modeling of the long term behavior of Municipal Solid Waste in a bioreactor landfill
Hubert, Julien ULg; Xianfeng, Liu; Collin, Frédéric ULg

in Computers and Geotechnics (2016), 72

This paper presents a thermo-hydro–biochemo-mechanical model for simulating the long term behavior of Municipal Solid Waste (MSW) in a bioreactor landfill, in which the multi-physics coupling mechanism ... [more ▼]

This paper presents a thermo-hydro–biochemo-mechanical model for simulating the long term behavior of Municipal Solid Waste (MSW) in a bioreactor landfill, in which the multi-physics coupling mechanism plays a dominant role. In the model, a two-stage anaerobic biochemical model based on McDougall’s formulation is incorporated into a fully coupled thermo-hydro-mechanical models originally developed for unsaturated porous medium. The mechanical model is a modified Camclay model allowing for biochemical hardening/softening, while the thermal model is described by a classical energy balance equation with a source term accounting for the heat generation from the biodegradation of organic matter. The hydraulic model is an unsaturated flow model using Richard’s equation. The derived coupled model is implemented into an in-house built multi-physics finite element code. Finally, numerical simulations were performed to illustrate the capability of the proposed model for estimating long-term settlement of a bioreactor landfill and its aptitude as a landfill management tool for optimizing the landfill operation [less ▲]

Detailed reference viewed: 29 (8 ULg)
Peer Reviewed
See detailTransformational Leadership, Role Conflict and the Moderating Role of Uncertainty Avoidance
Selzer, Veronika Luisa; Schumann, Jan Hendrik; Büttgen, Marion et al

Conference (2016, February)

Detailed reference viewed: 25 (1 ULg)
Full Text
See detailLa diversité des expressions culturelles au tourbillon du numérique
Vlassis, Antonios ULg

E-print/Working paper (2016)

Detailed reference viewed: 25 (2 ULg)
See detailGeschichtsvereine und Geschichtsbewusstsein in der DG (2. Teil)
Brüll, Christoph ULg

Article for general public (2016)

Detailed reference viewed: 24 (1 ULg)
Full Text
Peer Reviewed
See detailUse of dual carbon-chlorine isotope analysis to assess the degradation pathways of 1,1,1-trichloroethane in groundwater
Palau, Jordi; Jamin, Pierre ULg; Badin, Alice et al

in Water Research (2016)

Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater. However, the application of CSIA to chlorinated ethanes has received little attention so far. These ... [more ▼]

Compound-specific isotope analysis (CSIA) is a powerful tool to track contaminant fate in groundwater. However, the application of CSIA to chlorinated ethanes has received little attention so far. These compounds are toxic and prevalent groundwater contaminants of environmental concern. The high susceptibility of chlorinated ethanes like 1,1,1-trichloroethane (1,1,1-TCA) to be transformed via different competing pathways (biotic and abiotic) complicates the assessment of their fate in the subsurface. In this study, the use of a dual C-Cl isotope approach to identify the active degradation pathways of 1,1,1-TCA is evaluated for the first time in an aerobic aquifer impacted by 1,1,1-TCA and trichloroethylene (TCE) with concentrations of up to 20 mg/L and 3.4 mg/L, respectively. The reaction-specific dual carbon-chlorine (C-Cl) isotope trends determined in a recent laboratory study illustrated the potential of a dual isotope approach to identify contaminant degradation pathways of 1,1,1-TCA. Compared to the dual isotope slopes (Δδ13C/Δδ37Cl) previously determined in the laboratory for dehydrohalogenation / hydrolysis (DH/HY, 0.33 ± 0.04) and oxidation by persulfate (∞), the slope determined from field samples (0.6 ± 0.2, r2 = 0.75) is closer to the one observed for DH/HY, pointing to DH/HY as the predominant degradation pathway of 1,1,1-TCA in the aquifer. The observed deviation could be explained by a minor contribution of additional degradation processes. This result, along with the little degradation of TCE determined from isotope measurements, confirmed that 1,1,1-TCA is the main source of the 1,1-dichlorethylene (1,1-DCE) detected in the aquifer with concentrations of up to 10 mg/L. This study demonstrates that a dual C-Cl isotope approach can strongly improve the qualitative and quantitative assessment of 1,1,1-TCA degradation processes in the field. [less ▲]

Detailed reference viewed: 39 (7 ULg)
Full Text
Peer Reviewed
See detailNew perspectives for the design of sustainable bioprocesses for phosphorus recovery from waste
Tarayre, Cédric ULg; De Clercq, Lies; Charlier, Raphaëlle et al

in Bioresource Technology (2016), 206

Phosphate rock has long been used for the production of phosphorus based chemicals. However, considering the depletion of the reservoirs and the decrease of the quality of phosphate rocks, a potential ... [more ▼]

Phosphate rock has long been used for the production of phosphorus based chemicals. However, considering the depletion of the reservoirs and the decrease of the quality of phosphate rocks, a potential market is now emerging for the recovery of phosphate from waste and its reuse for different applications. Notably, phosphate recovery from wastewater could be included in a circular economy approach. This review focuses on the use of microbial systems for phosphorus accumulation and recovery, by considering the actual range of analytical techniques available for the monitoring of phosphorus accumulating organisms, as well as the actual biochemical and metabolic engineering toolbox available for the optimization of bioprocesses. In this context, knowledge gathered from process, system and synthetic biology could potentially lead to innovative process design. [less ▲]

Detailed reference viewed: 26 (2 ULg)
Full Text
Peer Reviewed
See detailDoes biobased polymer achieve better environmental impacts than fossil polymer? Comparison of fossil HDPE and biobased HDPE produced from sugar beet and wheat
Belboom, Sandra ULg; Léonard, Angélique ULg

in Biomass & Bioenergy (2016), 85

Polymers are one of the most used materials and the majority of their production is based on fossil fuels. Due to the decrease of oil resources and concerns about climate change, alternatives are needed ... [more ▼]

Polymers are one of the most used materials and the majority of their production is based on fossil fuels. Due to the decrease of oil resources and concerns about climate change, alternatives are needed, the transformation of biobased ethanol into biobased polymer being one of them. This paper undertakes an environmental evaluation of the production of biobased polymer produced from two different feedstock cultivated in Belgium: sugar beet and wheat. Both crops cultivation are studied as well as their transformation into biobased ethanol, first, and then to biobased ethylene, focusing on high-density polyethylene (HDPE) as final product. These scenarios are analyzed and compared with the production of conventional polymer using the life-cycle assessment (LCA) methodology with reference to relevant environmental impact categories. This study shows a reduction of impact of around 60% for both climate change and fossil fuel depletion categories when using biobased HDPE instead of its fossil counterpart. For all other impact categories, fossil HDPE achieves better results than the biobased product. [less ▲]

Detailed reference viewed: 52 (6 ULg)
Full Text
Peer Reviewed
See detailL'énonciation énoncée dans l'image
Dondero, Maria Giulia ULg

in Colas-Blaise, Marion; Tore, Gian Maria; Perrin, Laurent (Eds.) Le sens de l’énonciation (2016)

Le propos de cet article est de rendre compte des développements de la théorie de l’énonciation à la suite de la proposition d’Emile Benveniste d’étendre ce concept à la musique et à d’autres langages non ... [more ▼]

Le propos de cet article est de rendre compte des développements de la théorie de l’énonciation à la suite de la proposition d’Emile Benveniste d’étendre ce concept à la musique et à d’autres langages non verbaux. Un retour sur cette question se révèle aujourd’hui nécessaire pour plusieurs raisons. Certaines sont internes à la discipline et aux sciences du langage — la légitimité du visuel en tant que langage —, d’autres sont extra-disciplinaires, venant surtout des sciences de la communication et de la philosophie de l’art. Nous aborderons ici deux questions fondamentales concernant l’énonciation dans le visuel, étroitement liées entre elles. La première concerne la subjectivité inscrite dans l’image et sera approchée via la notion d’énonciation énoncée (personne/espace/temps). L’analyse énonciative de l’énoncé visuel vise en effet à décrire « d’où l’on voit », à savoir les points de vue à partir desquels l’image a été conçue et demande à être saisie par le regard de l’observateur. La deuxième question concerne la notion de métalangage. Comme l’a affirmé Jacques Fontanille, l’énonciation est « un métalangage "descriptif" car, en prédiquant l’énoncé, elle affiche sa propre activité, elle la code et en fait un événement sensible ou observable » (Sémiotique du discours, 2003, p. 283). Une première interrogation émerge alors : peut-on parler de métalangage dans le cadre du visuel, où il est d’ailleurs déjà difficile de repérer une véritable langue visuelle, dotée d’un alphabet de signes disjoints et d’une grammaire figée ? [less ▲]

Detailed reference viewed: 92 (8 ULg)
See detailResponses to Death, Care and Family Relations in Urban Senegal
Evans, Ruth; McCarthy, Jane Ribbens; Bowlby, Sophie et al

Report (2016)

Detailed reference viewed: 13 (3 ULg)
Full Text
See detailContextualisation de la pensée d'Albert Demaret et réflexion autour du déni anorexique
Mormont, Christian ULg

in Englebert, Jérôme; Follet, Valérie (Eds.) Adaptation. Essai collectif à partir des paradigmes éthologiques et évolutionnistes. (2016, February)

Contextualization of thoughts and works of Albert Demaret in the field of psychiatry and ethology. About the disavowal in anorectic female.

Detailed reference viewed: 36 (2 ULg)
Full Text
Peer Reviewed
See detailProspects of a new dynamic simulation software for real-time applications on the Hydro-Québec system
Aristidou, Petros; Lebeau, Simon; Loud, Lester et al

in CIGRE Science and Engineering (2016), 4

Hydro-Québec has a long interest in on-line Dynamic Security Assessment (DSA) driven by its challenging system dynamics. Presently, off-line calculated security limits are combined with an on-line ... [more ▼]

Hydro-Québec has a long interest in on-line Dynamic Security Assessment (DSA) driven by its challenging system dynamics. Presently, off-line calculated security limits are combined with an on-line monitoring system. However, new developments in dynamic simulation enable real-time or near-real-time DSA calculations and transfer limits determination. In this paper, the domain-decomposition-based algorithm implemented in the simulator RAMSES is presented, along with techniques to accelerate its sequential and parallel executions. RAMSES exploits the localized response to disturbances and the timescale decomposition of dynamic phenomena to provide sequential acceleration when the simulation is performed on a single processing unit. Additionally, when more units are available, the parallelization potential of domain-decomposition methods is exploited for further acceleration. The algorithm and techniques have been tested on a realistic model of the Hydro-Québec system to evaluate the accuracy of dynamic responses and the sequential and parallel performances. Finally, the real-time capabilities have been assessed using a shared-memory parallel processing platform. [less ▲]

Detailed reference viewed: 26 (1 ULg)